TWI686653B - Display device - Google Patents

Abstract

The liquid crystal display device (LCD1, LCD2, LCD3) of the present invention includes: a display device substrate (100), an array substrate (200), and a display function layer held between the display device substrate (100) and the array substrate (200) 300), and the control department (120). The display device substrate (100) includes touch sensing wiring (3). The array substrate (200) includes: a common electrode (17) having one or more electrode portions (17A) provided in each of the plurality of pixel openings (18); a conductive wiring (30), insulated on the second Under the layer (12), it is electrically connected to the common electrode (17) and spans a plurality of pixel openings (18); the active element (28) is provided under the third insulating layer (13) and connected to the pixel electrode (20) Thin-film transistor of top gate structure electrically connected; gate wiring (10), having the same layer structure as the conductive wiring (30), formed between the second insulating layer and the third insulating layer and the conductive wiring (30 ) In the same position and extending in the second direction in plan view to be electrically connected to the active element; and the contact hole (H) is provided in the center of the longitudinal direction of the pattern of the electrode portion (17A) and is electrically connected Common electrode (17) and conductive wiring (30). The touch sensing wiring (3) and the common electrode (17) are opposed to each other in an oblique direction inclined with respect to the thickness direction of the display function layer (300).

Description

Display device

The present invention relates to a display device that can perform stable touch sensing and has high touch sensing sensitivity.

Display devices with a display function layer are used for large displays such as TVs, tablets, and smartphones. A liquid crystal display device using liquid crystal as a display function layer roughly has a structure in which a liquid crystal layer is sandwiched between two transparent substrates such as glass. The main liquid crystal driving method in such a liquid crystal display device can be roughly divided into a VA (Vertical Alignment) mode known as a vertical electric field method and an IPS (In-Plane Switching) mode known as a horizontal electric field method or FFS (Fringe Field Switching) mode.

From the viewpoint of thinning the display device, an organic EL device (OLED: Organic Light Emitting Diode) using an organic light-emitting diode as a display function layer has attracted attention. From the viewpoint of reducing power consumption, EMS (Electro Mechanical System) composed of electrical elements and mechanical elements has attracted attention. MEMS (Micro-Electro-Mechanical System) includes actuators, transducers, sensors, micro-mirrors, MEMS switches, optical parts such as optical films, and optical interference modulators (IMOD : Interferometric Modulation). In addition, in recent years, It is also known to arrange a plurality of micro LEDs on a display function layer on a substrate.

In the IPS mode or FFS mode, liquid crystal molecules are aligned horizontally with respect to the substrate surface of the liquid crystal display device, and an electric field is applied to the liquid crystal molecules in a direction approximately parallel to the substrate surface to drive the liquid crystal. The IPS mode or FFS mode is a liquid crystal driving method used in a liquid crystal display device having a wide viewing angle. The liquid crystal display device adopting the FFS mode has a great advantage that the liquid crystal can be driven at high speed by using fringe electric fields.

Regarding the driving method of the liquid crystal, in order to suppress burn-in of the liquid crystal display, polarity inversion driving (AC inversion driving) in which the positive and negative voltages applied to the liquid crystal layer are reversed after a predetermined image display period has passed. As a method of polarity inversion driving, there is known a dot inversion drive in which the polarities of the pixels are individually inverted, and the polarity of the pixels is inverted in a row unit in which the pixels are arranged along the horizontal direction of the screen. Horizontal line inversion drive; column inversion drive in which the polarity of pixels is reversed in a column unit in which a plurality of pixels are arranged along the longitudinal direction of the screen; the pixel polarity is reversed in one screen unit, or in plural A block divides the screen and inverts the frame in which the polarity of the pixel is reversed in block units. Such a liquid crystal driving technique is described or suggested in Patent Documents 1 to 5, 7 for example.

As such a liquid crystal display device, recently, a liquid crystal display device having a touch sensing function equipped with a means for detecting capacitance is often used. As a touch sensing method, a touch sensing wiring (touch electrode) arranged for example in the X direction and the Y direction is mainly used to detect the current hand A method of changing capacitance when a pointer such as a finger or a pen touches or approaches the display screen.

In addition, as a structure of a display device having a touch sensing function, an out-cell method of attaching a touch panel having a touch sensing function to the surface of the display device and the display device itself are known In-cell method with touch sensing function. In recent years, many display devices have adopted an in-line method compared to an external method.

Patent documents 2 to 6 disclose touch sensing technology using an embedded method. Nonetheless, in terms of the embedded method, these patent documents have successively appeared unclear problems of touch sensing technology. In other words, there is a problem that it is difficult to become a problem in terms of the manner of attaching the touch panel, that is, the touch sensing wiring is susceptible to noise from the source wiring electrically connected to the active element provided inside the liquid crystal cell (noise) ) Affects such new technical issues.

Patent Literature 1 relates to liquid crystal driving, and discloses a technique of inverting the polarities of pixels in a column unit in which a plurality of pixels are arranged along the longitudinal direction of the screen. Patent Literature 1 does not include touch sensing technology.

Patent Literature 2 contains descriptions related to dot inversion driving, and discloses a touch sensing technology. In the disclosure of Patent Document 2, the drive electrode and the detection electrode that perform the touch sensing function are substantially composed of metal wiring.

Patent Document 3 relates to an in-plane switching (IPS) liquid crystal display, and discloses techniques for detecting touch sensing driving electrodes to form touch sensing signals and electrode pairs used in the display. The disclosure of Patent Document 3 is similar to the feature points of claim 2 described in Patent Document 5.

Patent Document 4 discloses a structure in which a touch screen is incorporated in a liquid crystal display device of a longitudinal electric field type in which opposing electrodes are stacked on a color filter. Such a structure is exemplified in claim 1 and the embodiment of Patent Document 4, for example. In addition, as described in claim 1 of Patent Document 4, display pixels include accumulation capacitors. In addition, the touch drive electrode is operated as the counter electrode of the accumulation capacitor during the display operation. Furthermore, after paragraph 0156 of Patent Document 4, it is disclosed that two types of electrodes of in-plane switching (IPS) are parallel to each other in a single plane. Paragraph 0157 of Patent Document 4 indicates that the IPS display lacks a Vcom layer that can be used for touch driving or touch sensing.

In the structure disclosed in Patent Document 4, yVcom must crossover xVcom (paragraph 0033 of Patent Document 4, and Figure 5, Figure 1E, Figure 1F, etc.).

Patent Literature 5 discloses a touch sensing technology using orthogonal strip conductors in a liquid crystal cell.

Patent Document 6 discloses a plurality of touch drive electrodes (connected to the interconnection wire xVcom as a driving region) made of a transparent material and extending in the first direction, and a plurality of touches extending in the second direction The detection electrode (connected with yVcom as a sensing area), one of the touch drive electrode and the touch detection electrode functions as a counter electrode of the liquid crystal display.

Patent Literature 6 discloses a technique of performing touch sensing between a first group of driving lines including a plurality of display pixels and a second group of sensing lines including a plurality of display pixels. An extremely complicated structure in which a bypass channel (by-pass tunnel) is provided between the circuit elements of the second group.

Patent Document 7 discloses a method of suppressing the decrease in image quality when performing line sequential scanning of liquid crystal driving. In Patent Document 7, a polycrystalline silicon semiconductor is used as an active element (TFT: Thin Film Transistor) for driving liquid crystals. In addition, a transfer circuit including a latch portion is provided to maintain the potential, thereby preventing the potential of the scan signal line inherent in the polycrystalline silicon TFT having a large amount of off-leak current (off-leak current) from decreasing, and preventing the image quality of the liquid crystal display from being reduced.

In addition, as can be seen from the descriptions in FIG. 6, FIG. 7, and paragraph 0035 of Patent Document 7, the touch detection electrodes and the pixel signal lines are parallel, and are configured to overlap in a plan view. Originally, the S/N ratio (especially "S", the value of the signal) can be improved by shortening the distance between the touch detection wiring and the drive electrode COML of the touch. Nevertheless, in the structure in which the touch detection electrode and the pixel signal line are formed in a long line shape and overlapped in the longitudinal direction of the pixel in a plan view, the proximity of the touch detection electrode and the pixel signal line makes the The parasitic capacitance generated between the above two lines becomes larger. In other words, "N" (noise) generated from the pixel signal line is easily applied to the touch detection electrode, and as a result, it is difficult to increase the S/N ratio.

Paragraph 0064 of Patent Document 8 discloses the formation of metal wiring of a three-layer structure composed of an indium-containing layer/copper/indium-containing layer, as a signal line of a thin film transistor, a scanning line, and a liquid crystal drive The wiring structure of the auxiliary capacitor line.

In addition, Patent Document 8 discloses a structure including a signal line (source line) or a pixel electrode in a touch sensing space described later. The signal line (source line) or pixel electrode becomes a source of noise, so no consideration is given to reducing the influence of noise caused by the signal (image signal) on touch sensing. E.g, The fourth embodiment of Patent Document 8 or FIG. 11 discloses a structure in which a pixel electrode is provided on a common electrode used for touch sensing and formed with a transparent conductive film such as ITO. The pixel electrode is applied with a liquid crystal drive voltage that frequently replaces the signal for image display supplied through the source line. Therefore, the structure shown in FIG. 11 including the pixel electrode on the common electrode is not good. In addition, the fifth embodiment or the twelfth embodiment of Patent Document 8 discloses a structure in which a source wiring is provided on the touch sensing wiring in addition to the pixel electrode. Therefore, it is easy to accidentally obtain more noise or parasitic capacitance than the structure shown in FIG. 11, and from this point of view, a structure that is not optimal is disclosed. In the example shown in FIG. 12, the gate line is located at the lowermost part in the Y direction, and the thin film transistor has a bottom-gate structure.

The technologies disclosed in Patent Literature 1 to Patent Literature 8 do not fully consider the means of reducing the noise caused by the source wiring given to the image signal for each image display, making it difficult to provide high-sensitivity touch sensing technology. In addition, it is insufficient in terms of suppressing noise generation related to liquid crystal driving.

Prior technical literature Patent Literature

Patent Document 1 Japanese Patent Publication No. 4-22486

Patent Document 2 Japanese Patent Application Publication No. 2014-109904

Patent Literature 3 Japanese Patent No. 4584342

Patent Document 4 Japanese Patent No. 5517611

Patent Literature 5 Japanese Patent Laid-Open No. 7-36017

Patent Literature 6 Japanese Patent No. 5746736

Patent Document 7 Japanese Patent Application Publication No. 2014-182203

Patent Literature 8 Japanese Patent No. 5807726

In terms of the display device adopting the embedded method and having a touch sensing function, in terms of improving the sensing sensitivity, countermeasures for noise due to liquid crystal driving are indispensable.

As described above, in order to avoid sticking due to charge accumulation, polarity inversion driving is generally adopted as liquid crystal driving. In spite of this, the source wiring that transmits the image signal becomes a source that generates noise due to polarity reversal. In addition, the source wiring is easily accompanied by changes in the parasitic capacitance accompanying the inversion of the polarity of the video signal. In a display device that uses an embedded method and has a touch sensing function, it becomes important to control the generation of noise caused by the source wiring that transmits image signals.

In addition, as disclosed in Patent Document 6, the array substrate (TFT substrate) has a touch sensing function in a position very close to the signal wiring such as the source wiring or gate wiring of the driving active element (TFT), and These wires are arranged in parallel with wires related to touch sensing (hereinafter referred to as touch sensing wires). In particular, source wiring using various voltages and transmitting image signals at a high frequency has a huge adverse effect on touch sensing wiring.

In an active device using a polysilicon semiconductor as the channel layer of the transistor, the leakage current is large, and the image signal must be updated frequently, and there is a concern that noise generated by the source wiring will affect the touch sensing wiring. In addition, in the structure where the TFT substrate has a touch sensing function, the sensing line (touch Control signal detection wiring), drive line (touch-sensing drive wiring), and source wiring or gate wiring for driving active components are all installed on an array substrate. Road channel, etc. That is, a complicated structure that leads to high costs becomes necessary.

In addition, in order to reduce the leakage current of the polysilicon semiconductor, it is necessary to adopt a double gate structure in which two TFTs are connected to the pixel electrode in each pixel. However, the double gate structure becomes a factor of high cost and reduces the aperture ratio of the pixel.

The present invention has been accomplished in view of the above-mentioned problems, and provides a liquid crystal display device that reduces the influence of noise that affects touch sensing in the liquid crystal display device of the horizontal electric field type represented by the FFS mode.

A display device according to an aspect of the present invention includes a display device substrate, an array substrate, a display function layer, and a control unit. The display device substrate includes a first transparent substrate, and a first transparent substrate provided on the first transparent substrate The touch sensing wiring extending in the direction, the array substrate includes: a second transparent substrate; a plurality of polygonal pixel openings on the second transparent substrate; a common electrode having each provided in the plurality of pixel openings One or more electrode portions extending in the first direction in a plan view; a first insulating layer provided under the common electrode; and a pixel electrode provided in each of the plurality of pixel openings Under the first insulating layer; the second insulating layer is provided under the pixel electrode; the conductive wiring is electrically connected to the common electrode under the second insulating layer, and in the second direction orthogonal to the first direction square Extending upwards across the plurality of pixel openings; the third insulating layer is provided under the conductive wiring; the active element is a thin film of a top gate structure provided under the third insulating layer and electrically connected to the pixel electrode Transistor; gate wiring, having the same layer structure as the conductive wiring, formed between the second insulating layer and the third insulating layer at the same position as the conductive wiring, and in the second direction in a plan view Extending upward to be electrically connected to the active element; source wiring extending in the first direction in a plan view to be electrically connected to the active element; and contact holes provided in the longitudinal direction of the pattern of the electrode portion The center is electrically connected to the common electrode and the conductive wiring, the display function layer is sandwiched between the display device substrate and the array substrate, and the control unit is driven by applying between the pixel electrode and the common electrode The voltage drives the display function layer to perform image display, and detects a change in capacitance between the common electrode and the touch sensing wiring for touch sensing. The touch sensing wiring and the common electrode system are opposed to each other in an oblique direction inclined with respect to the thickness direction of the display function layer.

The "display function layer" in one aspect of the present invention means a layer that realizes functions such as light transmission, light shielding, light reflection, or light emission between the electrodes. Examples of such a display function layer include liquid crystal elements, organic EL elements, EMS elements, MEMS elements, IMOD elements, and micro LED elements.

In the display device according to an aspect of the present invention, the common electrode may have a stripe pattern extending in a longitudinal direction parallel to the touch sensing wiring in a plan view.

In the display device according to one aspect of the present invention, the active element may include a channel layer made of an oxide semiconductor, and the channel layer is a thin film transistor in contact with the gate insulating film.

In the display device according to one aspect of the present invention, the oxide semiconductor may be an oxide semiconductor including two or more metal oxides among gallium, indium, zinc, tin, aluminum, germanium, antimony, bismuth, and cerium.

In the display device of one aspect of the present invention, the gate insulating film may be a gate insulating film formed of a composite oxide containing cerium oxide.

In the display device according to an aspect of the present invention, the display function layer is a liquid crystal layer, and the liquid crystal of the liquid crystal layer may have an initial alignment parallel to the array substrate, and is applied between the common electrode and the pixel electrode. The fringe electric field generated by the driving voltage of the liquid crystal is driven.

In the display device of one aspect of the present invention, the common electrode and the pixel electrode may be composed of a composite oxide containing at least indium oxide and tin oxide.

In the display device of one aspect of the present invention, the touch sensing wiring may be composed of a metal layer including a copper alloy layer.

In the display device of one aspect of the present invention, the touch sensing wiring may have a structure in which the copper alloy layer is sandwiched by the conductive metal oxide layer.

In the display device of one aspect of the present invention, the conductive wiring may have a structure in which the copper alloy layer is sandwiched by the conductive metal oxide layer.

In the display device of one aspect of the present invention, the conductive metal oxide layer may be a composite oxide layer containing two or more of indium oxide, zinc oxide, antimony oxide, and tin oxide.

In the display device according to an aspect of the present invention, the display device substrate may include a black matrix provided between the first transparent substrate and the touch sensing wiring, and the touch sensing wiring may be Partly overlapping.

In the display device according to an aspect of the present invention, the display device substrate may include a color filter provided at a position corresponding to a plurality of pixel openings.

According to one aspect of the present invention, it is possible to provide a liquid crystal display device that reduces noise that adversely affects touch sensing and simplifies the wiring structure related to touch sensing. In addition, it is possible to realize a structure that does not include source wiring or pixel electrodes supplied to the image signal in the touch sensing space, and can reduce noise related to the image signal.

3‧‧‧Touch sensing wiring

4‧‧‧Second conductive metal oxide layer (conductive metal oxide layer)

5‧‧‧Metal layer

6‧‧‧The first conductive metal oxide layer (conductive metal oxide layer)

8‧‧‧Black layer

10‧‧‧Gate wiring

11‧‧‧The first insulating layer

11F‧‧‧Filling Department

11H‧‧‧Through hole

11T‧‧‧Top surface

12‧‧‧The second insulating layer

12H‧‧‧Through hole

12T‧‧‧Top surface

13‧‧‧The third insulating layer

13A‧‧‧Protrusion

14‧‧‧The fourth insulating layer

16‧‧‧Transparent resin layer

17‧‧‧Common electrode

17A‧‧‧Electrode

17B‧‧‧Conductive connection

17K‧‧‧Wall

18‧‧‧Pixel opening

20‧‧‧Pixel electrode

20K‧‧‧Inner wall

20S‧‧‧Through hole

21‧‧‧Transparent substrate (1st transparent substrate)

22‧‧‧Transparent substrate (second transparent substrate)

24‧‧‧Source electrode

25‧‧‧Gate electrode

26‧‧‧ Drain electrode

27‧‧‧channel layer

28‧‧‧Active components

29‧‧‧Contact hole

30‧‧‧Common wiring (conductive wiring)

31‧‧‧Source wiring

33‧‧‧Power line

34‧‧‧Terminal

39‧‧‧Liquid crystal molecules

43H‧‧‧3rd contact hole (contact hole)

51‧‧‧Color filter

100‧‧‧Display device substrate

110‧‧‧Display

120‧‧‧Control Department

121‧‧‧Image signal control department

122‧‧‧Touch Sensing Control Department

123‧‧‧System Control Department

200‧‧‧Array substrate

206‧‧‧Liquid crystal layer

213‧‧‧ transparent resin layer

214‧‧‧ color filter

215‧‧‧Transparent substrate

221‧‧‧counter electrode

250‧‧‧LCD display device

250A‧‧‧LCD display device

300‧‧‧Liquid crystal layer

BM‧‧‧Black Matrix

BU‧‧‧Backlight unit

W17A‧‧‧Width

D20S‧‧‧Diameter

EL‧‧‧Length

H‧‧‧Contact hole

L‧‧‧Light

L2‧‧‧equipotential line

L3‧‧‧equipotential line

LH‧‧‧Left contact hole (1st contact hole)

RH‧‧‧Right contact hole (2nd contact hole)

LCD1‧‧‧Liquid crystal display device

LCD2‧‧‧Liquid crystal display device

LCD3‧‧‧Liquid crystal display device

P17A‧‧‧spacing

Pa‧‧‧Upper area

Pb‧‧‧lower area

Rub‧‧‧Alignment processing direction

W1‧‧‧Distance between touch sensing wiring and common electrode

W2‧‧‧Distance between touch sensing wiring and source wiring

W3‧‧‧Altitude

W4‧‧‧Distance between touch sensing wiring and gate wiring

θ‧‧‧angle (inclination from the longitudinal direction of pixel opening Y)

Fig. 1 is a block diagram showing a control unit (image signal control unit, system control unit, and touch sensing control unit) and a display unit constituting the display device according to the first embodiment of the present invention.

FIG. 2 is a plan view partially showing the array substrate constituting the display device according to the first embodiment of the present invention, as viewed from the observer side.

FIG. 3 is a cross-sectional view partially showing the display device according to the first embodiment of the present invention, taken along line A-A' shown in FIG. 2.

Fig. 4A is a cross-sectional view partially showing the display device according to the first embodiment of the present invention, taken along the line B-B' shown in Fig. 2.

FIG. 4B is an enlarged cross-sectional view partially showing the display device according to the first embodiment of the present invention, and showing an enlarged common electrode.

Fig. 5 is a cross-sectional view partially showing the display device according to the first embodiment of the present invention, taken along line C-C' shown in Fig. 2.

FIG. 6 is a plan view partially showing the display device according to the first embodiment of the present invention, which is displayed on the array substrate shown in FIG. 2 through a liquid crystal layer, a display including a color filter and a touch sensing wiring layer A plan view of the structure of the device substrate.

Fig. 7 is a partial cross-sectional view of the display device substrate according to the first embodiment of the present invention, taken along line F-F' shown in Fig. 6.

FIG. 8 is a cross-sectional view partially showing the display device substrate according to the first embodiment of the present invention, and a cross-sectional view illustrating the terminal portion of the touch sensing wiring.

FIG. 9 is a cross-sectional view partially showing the display device substrate of the first embodiment of the present invention, and a cross-sectional view illustrating the terminal portion of the touch sensing wiring.

FIG. 10 is a plan view partially showing the array substrate of the first embodiment of the present invention, illustrating one step among the manufacturing steps of the array substrate, and showing the pattern of the channel layer of a constituent element of the active device. In FIG. 10, the broken line indicates the positions of the source wiring and the gate wiring formed after the subsequent steps.

FIG. 11 is a plan view partially showing the array substrate of the first embodiment of the present invention, illustrating a plan view of one of the manufacturing steps of the array substrate, showing the formation of source wiring, source electrodes, and drain electrodes on the channel layer Plan view of the structure of each pattern.

FIG. 12 is a plan view partially showing the array substrate of the first embodiment of the present invention, illustrating a plan view of one of the manufacturing steps of the array substrate, showing the formation of the gate electrode, gate wiring, and conduction through the gate insulating film A plan view of the structure of each pattern of wiring. In FIG. 12, each of the gate electrode, the gate wiring, and the conductive wiring has a laminated structure formed of a plurality of layers including a metal layer and the like.

FIG. 13 is a plan view partially showing the array substrate of the first embodiment of the present invention, a plan view illustrating one of the manufacturing steps of the array substrate, and a plan view showing the structure of the pixel electrode pattern formed through the insulating layer. In addition, the laminated structure shown in FIG. 13 in which the common electrode is formed through the insulating layer on the array substrate corresponds to the structure shown in FIG. 2 described above.

FIG. 14 is a timing chart showing an example of time-division driving of liquid crystal driving and touch sensing driving in the display device according to the embodiment of the present invention.

FIG. 15 is a plan view partially showing a pixel of the display device according to the first embodiment of the present invention, and showing a state of alignment of liquid crystal in one pixel.

FIG. 16 is a plan view partially showing a pixel of the display device according to the first embodiment of the present invention, and a plan view showing the liquid crystal driving operation when a liquid crystal driving voltage is applied between the pixel electrode and the common electrode.

FIG. 17 shows that in the display device according to the first embodiment of the present invention, when the touch sensing wiring functions as a touch drive electrode and the common electrode functions as a touch detection electrode, the touch A schematic cross-sectional view of a state in which an electric field is generated between the sensing wiring and the common electrode.

FIG. 18 is a schematic cross-sectional view showing the display device according to the first embodiment of the present invention, showing a change in the state of electric field generation when a pointer such as a finger touches or approaches the surface of the display device substrate on the observer side. Figure.

FIG. 19 is a cross-sectional view partially showing a main part of an array substrate constituting a display device according to a modification of the first embodiment of the present invention.

FIG. 20 is a plan view partially showing the array substrate constituting the display device of the second embodiment of the present invention, as viewed from the observer side.

Fig. 21 is a partial cross-sectional view of the array substrate constituting the display device of the second embodiment of the present invention, taken along the line D-D' shown in Fig. 20.

22 is a plan view partially showing a plan view of a display device according to a second embodiment of the present invention, which is a plan view showing the structure of a display device substrate laminated on an array substrate, through a liquid crystal layer, with a color filter and touch sensing wiring stacked , A plan view from the observer's side.

Fig. 23 is a partial cross-sectional view of an array substrate constituting a display device according to a second embodiment of the present invention, taken along the line E-E' shown in Fig. 20.

Fig. 24 is a plan view partially showing a pixel of a display device according to a second embodiment of the present invention, and showing a state of alignment of liquid crystal in one pixel.

FIG. 25 is a plan view partially showing a pixel of a display device according to a second embodiment of the present invention, and a plan view showing a liquid crystal driving operation when a liquid crystal driving voltage is applied between a pixel electrode and a common electrode.

FIG. 26 is a cross-sectional view partially showing a display device using liquid crystal in the FFS mode, and a cross-sectional view showing a liquid crystal driving operation caused by an edge electric field when a liquid crystal driving voltage is applied between a pixel electrode and a common electrode.

FIG. 27 is a plan view partially showing an array substrate constituting a display device according to a third embodiment of the present invention.

FIG. 28 is a plan view partially showing a display device according to a third embodiment of the present invention, which is a plan view showing the structure of a display device substrate on an array substrate, through a liquid crystal layer, laminated with a color filter and touch sensing wiring , A plan view from the observer's side.

FIG. 29 is a cross-sectional view partially showing an array substrate constituting a display device according to a third embodiment of the present invention.

FIG. 30 is a cross-sectional view schematically showing a display portion of a conventional liquid crystal display device together with equipotential lines.

FIG. 31 is a cross-sectional view schematically showing a modification of the display unit of the conventional liquid crystal display device together with equipotential lines.

FIG. 32 is an enlarged plan view showing one pixel of the conventional liquid crystal display device using the FFS mode.

[Form for carrying out the invention]

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

In the following description, the same or substantially the same functions and constituent elements are given the same reference symbols, and their descriptions are omitted or simplified, or they are explained only when necessary. In each drawing, since each constituent element is drawn to a size that is recognizable on the drawings, the size and ratio of each constituent element are appropriately different from those of the real thing. In addition, if necessary, elements that are difficult to illustrate are omitted, for example, the structure of forming a plurality of layers constituting an insulating layer, a buffer layer, and a channel layer of a semiconductor of a liquid crystal display device, and the structure of forming a plurality of layers of a conductive layer, etc. Show. As a substrate usable for a display device, a semiconductor substrate such as a glass substrate, a ceramic substrate, a quartz substrate, a sapphire substrate, silicon, silicon carbide, or silicon germanium, or a plastic substrate can be used.

In each of the embodiments described below, the characteristic parts will be described. For example, the components used in the general liquid crystal display device and the display device of this embodiment are not different from each other, and the description is omitted.

In the following description, the wires, electrodes, and signals related to touch sensing are simply referred to as touch drive wiring, touch detection wiring, touch electrodes, and touch drive signals. The voltage applied to the touch sensing wiring for driving touch sensing is called a touch driving voltage, and the voltage applied between the common electrode and the pixel electrode to drive the liquid crystal layer of the display function layer is called a liquid crystal driving voltage. . The conductive wiring may be called common wiring.

In addition, the liquid crystal display device LCD1 of the embodiment of the present invention uses an in-line method. Here, the "embedded method" means a liquid crystal display device in which the touch sensing function is built in the liquid crystal display device, or a liquid crystal display device in which the touch sensing function and the liquid crystal display device are integrated. Generally, in a liquid crystal display device in which a display device substrate and an array substrate (TFT substrate) are bonded through a liquid crystal layer, a polarizing film is attached to the outer surfaces of the display device substrate and the array substrate. In other words, the in-cell liquid crystal display device of the embodiment of the present invention means that any part of the liquid crystal display device in the thickness direction between the two polarizing films facing each other is provided with touch sensing Functional liquid crystal display device.

(First embodiment) (Functional structure of liquid crystal display device LCD1)

Hereinafter, the liquid crystal display device LCD1 according to the first embodiment of the present invention will be described with reference to FIGS. 1 to 18.

FIG. 1 is a block diagram showing a liquid crystal display device LCD1 according to the first embodiment of the present invention. As shown in FIG. 1, the liquid crystal display device LCD1 of this embodiment includes a display unit 110 and a control unit 120 for controlling the display unit 110 and the touch sensing function.

The control unit 120 has a well-known structure, and includes an image signal control unit 121 (first control unit), a touch sensing control unit 122 (second control unit), and a system control unit 123 (third control unit).

The video signal control unit 121 sets the common electrode 17 (described later) provided on the array substrate 200 to a constant potential, and sends the signal to the gate wiring 10 (described later, scan line) provided on the array substrate 200 and the source wiring 31 ( (Described later, signal line). The video signal control unit 121 is A liquid crystal driving voltage for display is applied between the through electrode 17 and the pixel electrode 20 (described later) to generate a fringe electric field on the array substrate 200, the liquid crystal molecules rotate along the fringe electric field, and the liquid crystal layer 300 is driven. In this way, images are displayed on the array substrate 200. The plurality of pixel electrodes 20 are each transmitted through the source wiring (signal line) to individually apply image signals such as rectangular waves. In addition, the rectangular wave may be a positive or negative DC rectangular wave or an AC rectangular wave. The video signal control unit 121 sends such a video signal to the source wiring.

The touch-sensing control unit 122 applies a touch-sensing drive voltage to the touch-sensing wiring 3 (described later), detects a change in capacitance generated between the touch-sensing wiring 3 and the common electrode 17, and performs touch sensing Measurement.

The system control unit 123 controls the image signal control unit 121 and the touch sensing control unit 122 to detect the liquid crystal drive and the change in capacitance alternately, that is, time-sharing. In addition, the system control unit 123 may have a function of driving the liquid crystal at a frequency different from the liquid crystal driving frequency and the touch sensing driving frequency, or at a different voltage.

In the system control unit 123 having such a function, for example, the frequency of noise from the external environment accidentally obtained by the liquid crystal display device LCD1 is detected, and a touch sensing driving frequency different from the noise frequency is selected. In this way, the influence of noise can be reduced. In addition, in such a system control unit 123, it is also possible to select a touch sensing driving frequency that matches the scanning speed of a pointer such as a finger or a pen.

In the liquid crystal display device LCD1 having the structure shown in FIG. 1, the common electrode 17 also has the function of applying a liquid crystal driving voltage for display between the common electrode 17 and the pixel electrode 20 to drive the liquid crystal. And a touch sensing function that detects a change in capacitance generated between the touch sensing wiring 3 and the common electrode 17. Since the touch sensing wiring of the embodiment of the present invention can be formed of a metal layer having good conductivity, the resistance value of the touch sensing wiring can be reduced to improve the touch sensitivity (described later).

As will be described later, the control unit 120 preferably has a function that utilizes the touch sensing wiring 3 and the common electrode 17 during at least one of a stable period of image display and a black display stable period after image display. Touch sensing drive function.

(Structure of liquid crystal display device LCD1)

The liquid crystal display device of this embodiment can include the display device substrate of the embodiment described later. In addition, the “plan view” described below means a plane viewed from the direction in which the viewer views the display surface of the liquid crystal display device (the plane of the substrate for the display device). The shape of the display portion of the liquid crystal display device of the embodiment of the present invention, the shape of the pixel opening portion of the predetermined pixel, and the number of pixels constituting the liquid crystal display device are not limited. However, in the embodiments described in detail below, in a plan view, the direction of the short side of the pixel opening is defined as the X direction, and the direction of the long side (long side direction) is defined as the Y direction. The thickness direction is defined as the Z direction, which explains the liquid crystal display device. In the following embodiments, the X direction and the Y direction as defined above may be exchanged to constitute a liquid crystal display device.

In addition, in FIGS. 2 to 18, optical films such as an alignment film, a polarizing film, and a retardation film that provide initial alignment to the liquid crystal layer 300, a cover glass for protection, and the like are omitted. On the front and back surfaces of the liquid crystal display device LCD1, polarizing films are respectively attached so that the optical axis becomes cross polarized light (Cross Nicol).

FIG. 2 is a plan view partially showing an array substrate 200 constituting the liquid crystal display device LCD1 of the first embodiment of the present invention, as viewed from the observer side. In FIG. 2, in order to easily understand the structure of the array substrate for explanation, the illustration of the display device substrate facing the array substrate is omitted.

The liquid crystal display device LCD1 includes a plurality of source wirings 31, a plurality of gate wirings 10, and a plurality of common wirings 30 (conductive wirings) on the array substrate 200. The source wirings 31 are each formed to have a linear pattern extending in the Y direction (first direction). The gate wiring 10 and the common wiring 30 are each formed to have a linear pattern extending in the X direction (second direction). That is, the source wiring 31 is orthogonal to the gate wiring 10 and the common wiring 30. The common wiring 30 extends in the X direction so as to straddle a plurality of pixel openings. The plurality of pixel openings refer to the area defined on the transparent substrate 22.

In addition, the liquid crystal display device LCD1 includes a plurality of pixel electrodes 20 arranged in a matrix, and a plurality of active elements 28 (thin film transistors) provided in correspondence with the pixel electrodes 20 and connected to the pixel electrodes 20. The pixel electrode 20 is provided in each of the plurality of pixel openings. Specifically, each of the plurality of pixel electrodes 20 is connected to the active element 28. In the example shown in FIG. 2, the active element 28 is provided at the upper right end of the pixel electrode 20.

The active element 28 includes a source electrode 24 (described later) connected to the source wiring 31, a channel layer 27 (described later), a drain electrode 26 (described later), and a channel electrode 27 disposed opposite to the channel layer 27 through an insulating film (described later) Gate electrode 25. The gate electrode 25 of the active element 28 constitutes a part of the gate wiring 10 and is connected to the gate wiring 10.

In this embodiment, the liquid crystal display device LCD1 includes a plurality of pixels, and one pixel electrode 20 forms one pixel. With the switching drive by the active element 28, a voltage (positive and negative voltage) is applied to each of the plurality of pixel electrodes 20, and the liquid crystal is driven. In the following description, the region where the liquid crystal is driven by the pixel electrode 20 is sometimes referred to as a pixel, a pixel opening, or a pixel region. This pixel is a region separated by the source wiring 31 and the gate wiring 10 in a plan view.

In addition, the liquid crystal display device LCD1 includes a common electrode 17 at a position facing the pixel electrode 20 in the Z direction. In particular, two common electrodes 17 having a stripe pattern are provided for one pixel electrode 20. The common electrode 17 is provided in each of the plurality of pixel openings. The common electrode 17 extends in the Y direction and is parallel to the longitudinal direction of the pixel electrode 20. The length EL of the common electrode 17 in the Y direction is longer than the length of the pixel electrode 20 in the Y direction. The common electrode 17 is electrically connected to the common wiring 30 through a through hole 20S and a contact hole H described later. As shown in FIG. 2, the contact hole H is located at the center in the longitudinal direction of the conductive pattern (electrode portion 17A, stripe pattern) of the common electrode 17.

The number of common electrodes 17 and the number of contact holes in a pixel can be adjusted according to the pixel width (pixel size), for example.

In the X direction, the width W17A of the common electrode 17 is, for example, about 3 μm. The pitch P17A (distance) between the common electrodes 17 adjacent to each other is, for example, about 4 μm. Specifically, not only on one pixel, but also between pixels adjacent to each other, the common electrodes 17 are separated from each other by a pitch P17A in the X direction.

In the example shown in FIG. 2, two common electrodes 17 having a stripe pattern are provided for one pixel electrode 20, but the present invention is not limited to this structure. According to the size of the pixel electrode 20, the number of common electrodes 17 may be one or more, or even more than three. In this case, the width W17A and the pitch P17A of the common electrode 17 can be appropriately changed according to the pixel size or the like or the design.

Fig. 3 is a cross-sectional view partially showing a liquid crystal display device LCD1 according to the first embodiment of the present invention, taken along line A-A' shown in Fig. 2. In particular, FIG. 3 is a cross-sectional view along the short side direction of the pixel opening.

Fig. 4A is a cross-sectional view partially showing a liquid crystal display device LCD1 according to the first embodiment of the present invention, taken along the line B-B' shown in Fig. 2. FIG. 4B is an enlarged cross-sectional view partially showing a cross-sectional view of the liquid crystal display device LCD1 of the first embodiment of the present invention, and an enlarged common electrode.

Fig. 5 is a partial cross-sectional view of the liquid crystal display device LCD1 according to the first embodiment of the present invention, taken along the line C-C' shown in Fig. 2.

FIG. 3 or FIG. 4A shows the distance W1 between the touch sensing wiring 3 and the common electrode 17. In other words, this distance W1 is the distance in the Z direction in the space including the transparent resin layer 16, the color filter 51 (RGB), an alignment film (not shown), and the liquid crystal layer 300. The active element, source wiring, and pixel electrode are not included in this space. In this embodiment, this space represented by the distance W1 is called a touch sensing space. Noise generated from noise sources such as active components or source wiring is generally radiated into 3D radial. Therefore, the size of the noise becomes one third of the distance W1 (the greater the distance, the smaller the influence of noise becomes.).

FIG. 3 or FIG. 4A shows the distance W2 between the touch sensing wiring 3 and the source wiring 31. As shown by the distance W2, the touch sensing wiring 3 and the source wiring 31 are very apart. In addition, as shown in FIG. 2 or FIG. 3, the common electrode 17 and the source wiring 31 do not overlap in a plan view, so the parasitic capacitance caused by the source wiring 31 is extremely small. In addition, the common electrode 17 provided at the position closest to the touch sensing space has the shape of a thin strip in the pixel unit in the longitudinal direction of the pixel. Therefore, the common electrode 17 of this embodiment can reduce the parasitic capacitance compared to the case where the common electrode extending in a linear shape is provided so as to straddle a plurality of pixels.

If the structure shown in FIG. 3 or FIG. 4A is used, the influence of the noise caused by the image signal supplied to the source wiring 31 on the touch sensing wiring 3 can be suppressed, enabling touch sensing The parasitic capacitance generated between the wiring 3 and the source wiring 31 is reduced.

The liquid crystal display device LCD1 includes a display device substrate 100 (counter substrate), an array substrate 200 bonded to face the display device substrate 100, and a liquid crystal layer 300 held by the display device substrate 100 and the array substrate 200.

In the liquid crystal display device LCD1, the backlight unit BU that supplies light L internally is provided on the back surface of the array substrate 200 constituting the liquid crystal display device LCD1 (the surface opposite to the transparent substrate surface of the array substrate 200 where the liquid crystal layer 300 is disposed). In addition, the backlight unit may be provided on the side of the liquid crystal display device LCD1. In this case, for example, the light reflected from the backlight unit BU is reflected toward the inside of the liquid crystal display device LCD1 A plate, a light guide plate, a light diffusion plate, or the like are provided on the rear surface of the transparent substrate 22 of the array substrate 200.

(Display device substrate 100)

The display device substrate 100 includes a transparent substrate 21 (first transparent substrate), a touch sensing wiring 3 provided on the transparent substrate 21, and a color filter 51 (RGB) formed so as to cover the touch sensing wiring 3 And a transparent resin layer 16 formed to cover the color filter 51.

The touch sensing wiring 3 functions as a touch driving electrode (touch driving wiring). In the liquid crystal display device LCD1, touch sensing is detected by detecting a change in capacitance between the touch sensing wiring 3 and the common electrode 17.

The touch sensing wiring 3 has a laminated structure formed by at least a black layer 8 and a conductive layer including a metal layer 5 formed on the black layer 8. In addition, the conductive layer has a three-layer structure of a first conductive metal oxide layer 6, a metal layer 5, and a second conductive metal oxide layer 4. In addition, a black layer or a light-absorbing layer may be further deposited on the surface (liquid crystal layer side) of the first conductive metal oxide layer 6. In a plan view, there may be a portion where the line width of the touch sensing wiring 3 and the black layer 8 are equal.

The structure in which the metal layer 5 is sandwiched by the first conductive metal oxide layer 6 and the second conductive metal oxide layer 4 may also be a two-layer omitting either of the conductive metal oxides or the conductive oxide Layered layer structure.

(Metal layer 5)

As the metal layer 5, for example, a copper-containing layer of a copper layer or a copper alloy layer, or an aluminum alloy layer (aluminum-containing layer) containing aluminum can be used. in particular, As a material of the metal layer 5, copper, silver, gold, titanium, molybdenum, aluminum, or alloys thereof can be used. Nickel is a ferromagnetic body, so the film formation rate is reduced, but it can be formed by vacuum film formation such as sputtering. Chromium has a problem of environmental pollution or a large resistance value, but it can be used as a material for the metal layer of this embodiment. As the metal forming the metal layer 5, in order to obtain adhesion to the transparent substrate 21 or the transparent resin layer 16, it is preferable to add copper, aluminum, magnesium, calcium, titanium, molybdenum, indium, tin, zinc, or neodymium. , Nickel, aluminum, antimony, silver selected alloy of more than one metal element. If the amount of the metal element added to the metal layer 5 is 4 at% or less, the resistance value of the copper alloy or aluminum is not significantly reduced, which is preferable. As a copper alloy film forming method, for example, a vacuum film forming method such as sputtering can be used.

When a copper alloy thin film or an aluminum alloy thin film is used, if the film thickness is set to 100 nm or more or 150 nm or more, it becomes almost impossible to transmit visible light. Therefore, if the metal layer 5 of this embodiment has a film thickness of 100 nm to 300 nm, for example, sufficient light-shielding properties can be obtained. The film thickness of the metal layer 5 may exceed 300 nm. As described later, the material of the metal layer 5 can also be applied to the common wiring 30 (conductive wiring). In addition, the laminated structure in which the metal layer 5 is sandwiched by the conductive metal oxide layer can also be applied to the common wiring 30 (conductive wiring).

(Conductive metal oxide layer 4, 6)

The first conductive metal oxide layer 6 and the second conductive metal oxide layer 4 sandwich the metal layer 5. Nickel, zinc, indium, titanium, molybdenum, tungsten, etc. can be inserted into the interface between the first conductive metal oxide layer 6 and the metal layer 5 and the interface between the second conductive metal oxide layer 4 and the metal layer 5 Different metals or alloy layers of these metals.

Specifically, as the materials of the second conductive metal oxide layer 4 and the first conductive metal oxide layer 6, for example, two or more kinds selected from indium oxide, zinc oxide, antimony oxide, and tin oxide can be used. Composite oxide of metal oxides.

The amount of indium (In) contained in the second conductive metal oxide layer 4 and the first conductive metal oxide layer 6 must be more than 80 at%. The amount of indium (In) is preferably more than 80 at%. The amount of indium (In) is more preferably more than 90at%. When the amount of indium (In) is less than 80 at%, the specific resistance of the conductive metal oxide layer formed becomes large, which is not good. If the amount of zinc (Zn) exceeds 20 at%, the alkali resistance of the conductive metal oxide (mixed oxide) decreases, which is not good. Both the second conductive metal oxide layer 4 and the first conductive metal oxide layer 6 mentioned above are atomic percentages of metal elements in the mixed oxide (oxygen elements are not counted, only metal elements are counted). Antimony oxide can be added to the conductive metal oxide layer because antimony metal hardly forms a solid solution region with copper and suppresses the diffusion of copper in the laminated structure.

The amount of zinc (Zn) contained in the first conductive metal oxide layer 6 and the second conductive metal oxide layer 4 must be set to be greater than the amount of tin (Sn). If the tin content exceeds the zinc content, the wet etching in the subsequent steps causes hindrance. In other words, the metal layer of copper or copper alloy becomes easier to be etched than the conductive metal oxide layer, and the widths of the first conductive metal oxide layer 6, the metal layer 5, and the second conductive metal oxide layer 4 become It’s easy to make a difference.

The amount of tin (Sn) contained in the first conductive metal oxide layer 6 and the second conductive metal oxide layer 4 is preferably in the range of 0.5 at% or more and 6 at% or less. In comparison with the indium element, by adding 0.5at% or more and 6at% or less of tin to the conductive metal oxide layer, the ternary mixed oxide film of the above-mentioned indium, zinc, and tin can be reduced (conductivity Of the composite oxide layer). If the amount of tin exceeds 6 at%, zinc is added to the conductive metal oxide layer, so the specific resistance of the ternary mixed oxide film (conductive composite oxide layer) becomes excessive. By adjusting the amounts of zinc and tin within the above range (0.5 at% or more and 6 at% or less), the specific resistance can be incorporated into the specific resistance of the single-layer film of the mixed oxide film by about 3×10 ^-4 Within a small range of Ωcm or more and 5×10 ^-4 Ωcm or less. In the above mixed oxide, other elements such as titanium, zirconium, magnesium, aluminum, and germanium can also be added in small amounts. However, in this embodiment, the specific resistance of the mixed oxide is not limited to the above range.

When the metal layer 5 is a copper layer or a copper alloy layer, it is desirable that the above-mentioned conductive metal oxide layer contains two or more kinds of metal oxides selected from indium oxide, zinc oxide, antimony oxide, and tin oxide Compound oxide. The copper layer or the copper alloy layer has low adhesion to the transparent resin layer 16 constituting the color filter 51 or the glass substrate (transparent substrate 21). Therefore, in the case of directly applying a copper layer or a copper alloy layer to a display device substrate, it is difficult to realize a practical display device substrate. However, the aforementioned composite oxide has sufficient adhesion to the color filter 51, the black matrix BM (black layer 8), and the glass substrate (transparent substrate 21), etc., and to the copper layer or copper alloy layer Sex is enough. Therefore, when a copper layer or a copper alloy layer using a composite oxide is applied to a display device substrate, it becomes possible to realize a practical display device substrate.

Copper, copper alloy, silver, silver alloy, or their oxides and nitrides generally do not have sufficient adhesion to a transparent substrate 21 such as glass, a black matrix BM, or the like. Therefore, when the conductive metal oxide layer is not provided, peeling may occur at the interface between the touch sensing wiring 3 and the transparent substrate 21 such as glass, or at the interface between the touch sensing wiring 3 and the black layer 8. In the case of using copper or a copper alloy as the touch sensing wiring 3 with a fine wiring pattern, in terms of a display device substrate in which no conductive metal oxide layer is formed as a base layer of the metal layer 5 (copper or copper alloy), In addition to the defects caused by peeling, it is not practical to generate defects caused by electrostatic damage in the touch sensing wiring 3 during the manufacturing process of the display device substrate. Such electrostatic destruction in the touch sensing wiring 3 is due to the subsequent steps of stacking the color filter 51 on the transparent substrate 21, the step of bonding the display device substrate and the array substrate, or the cleaning step, etc. Static electricity accumulates in the wiring pattern, and the phenomenon of pattern defects, disconnection, etc. occurs due to static electricity destruction.

In addition, on the surface of the copper layer or the copper alloy layer, a copper oxide having no conductivity is formed as time passes, and electrical contact may become difficult. On the other hand, composite oxide layers such as indium oxide, zinc oxide, antimony oxide, and tin oxide can achieve stable ohmic contact, and when such a composite oxide layer is used, electrical properties such as transfer described below can be easily performed installation. In addition, in the sealing portion where the display device substrate and the array substrate are bonded, the conduction from the display device substrate 100 to the array substrate 200 may be transferred in the thickness direction of the sealing portion. The conductor selected from the anisotropic conductive film, the minute metal ball, the resin ball covered with the metal film, or the like is arranged in the sealing portion, and thus the display device substrate 100 and the array substrate 200 can be conducted.

Examples of the layer structure of the metal oxide in the conductive metal oxide layers 4 and 6 and the metal layer 5 applicable to the embodiment of the present invention include the following structures. For example, in the case of ITO (Indium Tin Oxide) or IZTO (Indium Zinc Tin Oxide, Z is zinc oxide) containing indium oxide as the central substrate, in the state of insufficient oxygen, for example, it can be exemplified by: The layer structure obtained by forming a metal layer on the layer, or by laminating a mixed oxide of molybdenum oxide, tungsten oxide, nickel oxide and copper oxide, titanium oxide, etc., and laminating the metal on an aluminum alloy or a copper alloy The resulting layer structure. The layer structure obtained by using the conductive metal oxide layer and the metal layer has the advantage of enabling continuous film formation in a vacuum film forming apparatus such as a sputtering apparatus.

(Black layer 8)

The black layer 8 functions as a black matrix BM of the liquid crystal display device LCD1. The black layer is composed of, for example, a coloring resin in which black color materials are dispersed. The oxide of copper or the oxide of copper alloy cannot obtain sufficient black or low reflectance, but the visible light reflectance at the interface between the black layer and the substrate such as glass in this embodiment is suppressed by almost 3% or less. High visibility.

As a black color material, carbon, nano carbon tubes, or a mixture of a plurality of organic pigments can be used. For example, carbon is used at a ratio of 51% by mass or more relative to the entire color material, that is, as a main color material. To adjust the reflection color, organic pigments such as blue or red can be added to the black color material. For example, the reproducibility of the black layer can be improved by adjusting the concentration of carbon contained in the photosensitive black coating liquid of the starting material (decreasing the carbon concentration).

In the case of a large exposure device using a manufacturing device of a liquid crystal display device, for example, a black layer (patterned) having a pattern having a width (thin line) of 1 to 6 μm can be formed. In addition, the range of the carbon concentration in the present embodiment is set within a range of 4% or more and 50% or less by mass relative to the entire solid content of the resin, hardener and pigment. Here, as the amount of carbon, the carbon concentration may exceed 50% by mass, but if the carbon concentration exceeds 50% by mass with respect to the solid content of the entirety, there is a tendency for the coating film property to decrease. In addition, when the carbon concentration is set to less than 4% by mass, sufficient black cannot be obtained, and the reflected light generated in the underlying metal layer under the black layer may be easily seen, which may reduce visibility.

When exposure processing is performed in the photolithography method in the subsequent step, alignment of the substrate to be exposed and the mask is performed. At this time, alignment is preferentially performed, and for example, the optical density of the black layer based on transmission measurement can be set to 2 or less. In addition to carbon, a mixture of a plurality of organic pigments may be used as a black color adjustment to form a black layer. Considering the refractive index (approximately 1.5) of the substrate such as glass or transparent resin, the reflectance of the black layer is set so that the reflectance at the interface between the black layer and those substrates becomes 3% or less. In this case, it is desirable to adjust the content and type of the black color material, the resin used in the color material, and the film thickness. By optimizing these conditions, the reflectance at the interface between the substrate such as glass having a refractive index of about 1.5 and the black layer can be set to 3% or less in the visible light wavelength range, and low reflectance can be achieved. In consideration of the necessity of preventing the reflected light from the light emitted from the backlight unit BU from being reflected again, and improving the visibility of the observer, it is desirable that the reflectance of the black layer is set to 3% or less. Also, in general, the acrylic used in the color filter The refractive index of the acid resin or liquid crystal material is approximately in the range of 1.5 or more and 1.7 or less.

In addition, the metal layer 5 used in the touch sensing wiring 3 can be suppressed by forming a metal oxide having light absorption on the touch sensing wiring 3 or the conductive wiring (common wiring 30) Light reflection.

In the display device substrate 100 shown in FIG. 3, a structure in which the color filter 51 is provided is used, but a structure in which the color filter 51 is omitted may be used, for example, a touch provided on the transparent substrate 21 The structure of the sensing wiring 3 and the transparent resin layer 16 formed so as to cover the touch sensing wiring 3.

In a liquid crystal display device using a display device substrate that does not include a color filter 51, each LED that emits red light, green light, and blue light is provided in a backlight unit, and color display is performed by a field sequence method. The layer structure of the touch sensing wiring 3 provided on the transparent substrate 21 shown in FIG. 3 can be set as a layer structure with the common wiring 30 (conductive wiring) formed on the array substrate 200 described later or the gate electrode 25 The layer structure of (gate wiring 10) is the same.

(Array substrate 200)

As shown in FIGS. 3, 4A, and 4B, the array substrate 200 includes a transparent substrate 22 (second transparent substrate), a fourth insulating layer 14 formed to cover the surface of the transparent substrate 22, and forming The source wiring 31 on the fourth insulating layer 14, the third insulating layer 13 formed on the fourth insulating layer 14 so as to cover the source wiring 31, and the gate wiring 10 formed on the third insulating layer 13, The common wiring 30 formed on the third insulating layer 13 is formed so as to cover the gate wiring 10 and the common wiring 30 The second insulating layer 12 on the third insulating layer 13, the pixel electrode 20 formed on the second insulating layer 12, the first insulating layer 11 formed on the second insulating layer 12 so as to cover the pixel electrode 20, and Common electrode 17.

As materials for forming the first insulating layer 11, the second insulating layer 12, the third insulating layer 13, and the fourth insulating layer 14, silicon oxide, silicon oxide nitride, aluminum oxide, aluminum oxide nitride, cerium oxide, Hafnium oxide, or a mixed material containing such materials. Alternatively, polyimide resin, acrylic resin, benzocyclobutene resin, or low-k material (low-k material) may be used for part of these insulating layers. In addition, as the structure of such insulating layers 11, 12, 13, and 14, a layer structure including a single layer may be adopted, or a multilayer structure in which a plurality of layers are stacked may be adopted. Such insulating layers 11, 12, 13, 14 can be formed using a film forming apparatus such as plasma CVD or sputtering.

The source wiring 31 is arranged between the third insulating layer 13 and the fourth insulating layer 14. As the structure of the source wiring 31, a multi-layer conductive layer can be used. In the first embodiment, a three-layer structure of titanium/aluminum alloy/titanium is used as the structure of the source wiring 31. Here, the aluminum alloy is an aluminum-neodymium alloy.

As the forming material of the common wiring 30, the same material as the metal layer 5 described above can be used. Also, as the structure of the common wiring 30, the same structure as the metal layer 5 described above can be adopted.

The pixel electrode 20 is provided in each of the plurality of pixel openings 18 and is connected to an active element (described later) of the TFT. In the array substrate 200, the active elements are arranged in a matrix, so the pixel electrodes 20 are similarly arranged in a matrix on the array substrate 200. The pixel electrode 20 is formed of a transparent conductive film such as ITO.

The channel layer or the semiconductor layer constituting the active device may be formed of a polycrystalline silicon semiconductor or an oxide semiconductor. The layer structure of the channel layer or the semiconductor layer constituting the active device may be a layered structure in which a polycrystalline silicon semiconductor and an oxide semiconductor are stacked. An element formed by using two kinds of semiconductors may be formed on the same surface of the array substrate, for example, an active element including a channel layer of a polycrystalline silicon semiconductor and an active element including a channel layer of an oxide semiconductor. Further, a structure in which a TFT array formed of an oxide semiconductor is laminated into two layers through an insulating layer on a TFT array of polysilicon semiconductor can be adopted. In the case where the display function layer is an organic EL (Organic Electroluminescence) layer, the TFT formed with an oxide semiconductor has the function of supplying a signal to the TFT (selective TFT element) formed with a polysilicon semiconductor, and the one formed with a polysilicon semiconductor The TFT has the function of driving the display function layer. With this structure, a display device using an organic EL layer as a display function layer can be realized. A TFT having a polycrystalline silicon semiconductor with a high carrier mobility and a polycrystalline silicon semiconductor as a channel layer is suitable for injecting current into the organic EL element (driving the organic EL element).

(Structure of common electrode 17)

With reference to FIG. 4B, the common electrode 17 and the constituent members of the array substrate 200 located around the common electrode 17 will be described. In particular, the laminated structure composed of the common wiring 30, the common electrode 17, the pixel electrode 20, the first insulating layer 11, and the second insulating layer 12 will be specifically described. FIG. 4B shows the main part of the pixels constituting the array substrate 200, and shows the structure of one common electrode 17 in one pixel. The total shown in Figure 4B The configuration of the through electrode 17 can also be applied to all pixels in the array substrate 200.

The second insulating layer 12 is provided under the first insulating layer 11, is formed on the common wiring 30, and has a through hole 12H that forms a part of a contact hole H described later. The first insulating layer 11 is provided under the common electrode 17 (the electrode portion 17A), is formed on the pixel electrode 20, and has a through hole 11H that forms a part of a contact hole H described later. The position (center position) of the through hole 12H and the position (center position) of the through hole 11H coincide. The diameter (width in the X direction) of the through hole 11H gradually decreases from the upper surface 11T of the first insulating layer 11 toward the common wiring 30 (Z direction). Similarly, the diameter (width in the X direction) of the through hole 12H gradually decreases from the upper surface 12T of the second insulating layer 12 toward the common wiring 30 (Z direction). The through hole 11H and the through hole 12H have continuous inner walls, and the contact hole H is formed. The contact hole H has a tapered shape.

The pixel electrode 20 is formed under the first insulating layer 11 and has a through hole 20S. The through hole 20S is an opening where no transparent conductive film exists. The through hole 20S is provided at a position corresponding to the contact hole H.

In the example shown in FIG. 2, two contact holes H are provided in each pixel, that is, the left contact hole LH (H, first contact hole) and the right contact hole RH (H, second contact hole), in The through hole 20S is provided at a position corresponding to each of the two contact holes H.

In the following description, the left contact hole LH and the right contact hole RH may be simply referred to as the contact hole H.

The through hole 20S corresponds to a region provided inside the inner wall 20K of the pixel electrode 20. The diameter D20S of the through hole 20S is smaller than that of the contact hole The diameter of H is large. The through hole 11H (part of the contact hole H) is provided inside the through hole 20S. The first insulating layer 11 is filled inside the through hole 20S, and the through hole 11H is formed so as to penetrate the filled portion 11F of the first insulating layer 11 buried in the inner wall of the through hole 20S. In addition, at a position below the through-hole 20S, a through-hole 12H (part of the through-hole H) is formed to be continuous with the through-hole 11H. The number of through holes 20S formed in the pixel electrode 20 is the same as the number of contact holes H, and they are formed at the same position in plan view. The diameter D20S of the through hole 20S is, for example, 3 μm to 6 μm. The diameter of the through hole 20S can be made larger than the width W17A of the common electrode 17.

The common electrode 17 includes an electrode portion 17A (conductive portion) and a conductive connection portion 17B. The electrode portion 17A is formed on the upper surface 11T of the first insulating layer 11 and is arranged so as to overlap the through hole 20S of the pixel electrode 20 when viewed from the Z direction. The electrode portion 17A is provided on the surface of the array substrate 200 closest to the liquid crystal layer 300. Specifically, an alignment film is formed between the liquid crystal layer 300 and the array substrate 200, and the first insulating layer 11 is provided under the alignment film.

The width W17A of the electrode portion 17A is, for example, about 3 μm, which is larger than the upper end of the conductive connection portion 17B (the connection portion between the electrode portion 17A and the conductive connection portion 17B), or may be formed larger than the diameter D20S (for example, 2 μm) of the through hole 20S . Alternatively, the diameter D20S of the through hole 20S is larger than the width W17A of the electrode portion 17A. The diameter D20S of the through-hole 20S can also be set to, for example, 4 μm. In the direction (X direction) from the center of the electrode portion 17A (the center line of the electrode portion 17A parallel to the Z direction) toward the outer side of the electrode portion 17A, the wall portion 17K of the electrode portion 17A is larger than the inner wall 20K of the pixel electrode 20 The location is also prominent.

The conductive connection portion 17B is provided inside the contact hole H (through holes 11H, 12H), and is electrically connected to the common wiring 30 through the contact hole H.

In the state where the above-mentioned contact holes are formed in the first insulating layer 11 and the second insulating layer 12, by performing the film forming step and the patterning step on the first insulating layer 11, the electrode portion 17A and the conductive connection portion 17B are integrally formed of. Like the pixel electrode 20, the common electrode 17 is formed of a transparent conductive film such as ITO.

In the above laminated structure, the first insulating layer 11 is disposed between the electrode portion 17A and the pixel electrode 20, and the second insulating layer 12 is disposed between the common wiring 30 and the pixel electrode 20. The wirings 30 are electrically connected to each other, and the potential of the common wiring 30 and the potential of the common electrode 17 are the same.

The potential of the common wiring 30 (or common electrode 17) can be changed in a time-sharing manner when liquid crystal driving and touch sensing driving (detection of capacitance change) are alternately performed. In addition, the frequency of the signal given to the common wiring 30 (or the common electrode 17) can be changed in a time-sharing manner when liquid crystal driving and touch sensing driving (detection of changes in capacitance) are alternately performed. In addition, when the liquid crystal is driven and the amplitude is reversed, the polarity of the potential of the common wiring 30 (or the common electrode 17) is replaced by positive and negative polarities, for example, a liquid crystal driving voltage of ±2.5V can be used to drive the liquid crystal .

When the liquid crystal drive is column inversion drive or dot inversion drive, the potential of the common electrode 17 may be constant (constant potential). The “constant potential” in this case refers to, for example, the potential of the common electrode 17 grounded to the housing of the liquid crystal display device through high resistance, and does not mean The fixed potential of ±2.5V etc. used for the aforementioned amplitude inversion drive. It is fixed at a constant potential of approximately 0 V (zero volts) within the range of the voltage below the critical value Vth of the liquid crystal. In other words, if it is within the range of Vth, the "constant potential" may be a constant potential that deviates from the middle value of the liquid crystal driving voltage. In addition, the above "high resistance" refers to a resistance value that can be selected from the range of 500 million ohms (megohm) to 50 megaohms (tera-ohm). As such a resistance value, for example, a representative 500 gigaohm to 5 megaohm can be used. When column inversion driving or dot inversion driving is adopted as the liquid crystal driving method, the common wiring 30 can be grounded through a high resistance of 1 megaohm, for example, and set to a constant potential of about 0 V (zero volt). In this case, the common electrode 17 connected to the common wiring 30 also has a constant potential of about 0 V (zero volts), and can reset the accumulated capacitance. When the potential of the common electrode 17 is set to a constant potential, the touch drive voltage is applied to the touch sensing wiring during touch sensing. When the potential of the common electrode 17 is set to “constant potential”, the liquid crystal drive and the touch drive can be driven without time-sharing.

In addition, in the case of using an oxide semiconductor such as IGZO as a material for forming a channel layer of an active element (thin film transistor) of a liquid crystal display device, in order to alleviate the state in which pixels of the liquid crystal display device are easily burned, a ratio of more than 1 trillion can be used. The low-ohmic resistance serves as the above-mentioned high resistance.

When the black display is described later, the gate wiring or the source wiring can be grounded through the above high resistance. In this case, pixel burn-in can be prevented.

In addition, the above-mentioned high resistance can be adjusted for the purpose of adjusting the time constant related to touch sensing. IGZO and other oxygen For the display device in which the compound semiconductor is used for the channel layer of the active device, the above various methods in touch sensing are feasible. In the following description, the oxide semiconductor may be abbreviated as IGZO.

(Active element 28)

Next, referring to FIG. 5, the structure of the active element 28 connected to the pixel electrode 20 will be described.

Fig. 5 shows an example of a thin film transistor (TFT) having a top gate structure.

The active element 28 includes a channel layer 27, a drain electrode 26 connected to one end of the channel layer 27 (the first end, the left end of the channel layer 27 in FIG. 5), and the other end of the channel layer 27 (the second end, The source electrode 24 connected to the right end of the channel layer 27 in FIG. 5 and the gate electrode 25 disposed opposite to the channel layer 27 through the third insulating layer 13. FIG. 5 shows a structure in which the channel layer 27, the drain electrode 26, and the source electrode 24 constituting the active element 28 are formed on the fourth insulating layer 14, but the present invention is not limited to this structure. The active element 28 may be directly formed on the transparent substrate 22 without being provided on the fourth insulating layer 14.

By supplying a video signal to the source wiring 31 at a high frequency, noise is easily generated from the source wiring 31. In terms of the top gate structure, there is an advantage that the source wiring 31, which is also a source of noise, can be moved away from the aforementioned touch sensing space.

The source electrode 24 and the drain electrode 26 shown in FIG. 5 are formed with conductive layers of the same structure in the same step. In the first embodiment, a three-layer structure of titanium/aluminum alloy/titanium is used as the structure of the source electrode 24 and the drain electrode 26. Here, the aluminum alloy is an aluminum-neodymium alloy.

The insulating layer 13 located under the gate electrode 25 may be an insulating layer having the same width as the gate electrode 25. In this case, for example, dry etching using the gate electrode 25 as a mask is performed to remove the insulating layer 13 around the gate electrode 25. With this, an insulating layer having the same width as the gate electrode 25 can be formed. The technique of processing the insulating layer by dry etching using the gate electrode 25 as a mask is generally called self-alignment.

As a material of the channel layer 27, for example, an oxide semiconductor called IGZO can be used. As a material of the channel layer 27, an oxide semiconductor containing two or more kinds of metal oxides among gallium, indium, zinc, tin, aluminum, germanium, antimony, bismuth, and cerium can be used. In this embodiment, an oxide semiconductor containing indium oxide, gallium oxide, and zinc oxide is used. The material of the channel layer 27 formed with an oxide semiconductor may be single crystal, polycrystalline, microcrystalline, a mixture of microcrystalline and amorphous, or any of amorphous. The film thickness of the oxide semiconductor can be a film thickness in the range of 2 nm to 50 nm. In addition, the channel layer 27 may be formed of polysilicon semiconductor.

An oxide semiconductor or a polycrystalline silicon semiconductor can be used, for example, in a structure of a complementary transistor having a p/n junction, or a structure of a single-channel transistor having only an n-junction. As the laminated structure of the oxide semiconductor, for example, a laminated structure of a laminated n-type oxide semiconductor and an n-type oxide semiconductor different from the electrical characteristics of the n-type oxide semiconductor can be used. The stacked n-type oxide semiconductor can be composed of a plurality of layers. In the stacked n-type oxide semiconductor, the band gap of the underlying n-type semiconductor can be made different from the band gap of the n-type semiconductor located above.

The upper surface of the channel layer may be used, for example, a structure covered with different oxide semiconductors.

Alternatively, for example, a layered structure in which a microcrystalline (nearly amorphous) oxide semiconductor is laminated on a crystalline n-type oxide semiconductor may be used. Here, the microcrystalline refers to, for example, a microcrystalline oxide semiconductor film in which an amorphous oxide semiconductor formed by a sputtering device is heat-treated within a range of 180°C or higher and 450°C or lower. Or, it refers to a microcrystalline oxide semiconductor film formed when the substrate temperature during film formation is set to about 200°C. The microcrystalline oxide semiconductor film system can observe an oxide semiconductor film having crystal grains of at least about 1 nm to 3 nm or larger than 3 nm by an observation method such as TEM.

The oxide semiconductor can improve the carrier mobility or increase the reliability by changing from amorphous to crystalline. For oxide, indium oxide or gallium oxide has a high melting point. The melting point of antimony oxide or bismuth oxide is below 1000°C, and the melting point of oxide is low. For example, in the case of using a ternary composite oxide of indium oxide, gallium oxide, and antimony oxide, the crystallization temperature of the composite oxide can be lowered by the effect of antimony oxide having a low melting point. In other words, an oxide semiconductor that can be easily crystallized from an amorphous state to a microcrystalline state can be provided.

As a stacked structure of semiconductors, an n-type oxide semiconductor may be stacked on an n-type polycrystalline silicon semiconductor. As a method for obtaining a layered structure using this polycrystalline silicon semiconductor as a base layer, it is preferable to form an oxide semiconductor film by sputtering or the like while maintaining a vacuum state after the polycrystalline silicon crystallization step using laser annealing. As an oxide semiconductor that can be applied to this method, due to the ease of wet etching required in the subsequent step Therefore, it is possible to use a composite oxide rich in zinc oxide. For example, the atomic ratio of the metal element as the target material used for sputtering can be exemplified by In:Ga:Zn=1:2:2. In this laminated structure, a structure in which no oxide semiconductor (for example, removed by wet etching) can be deposited only on the channel layer of polysilicon can be adopted.

In addition, a thin film transistor (active element) having a channel layer of an n-type oxide semiconductor and a thin film transistor (active element) having a channel layer of an n-type silicon semiconductor can be arranged in the same pixel for use The characteristics of each channel layer of a thin film transistor drive a display function layer such as a liquid crystal layer or an OLED. In the case of using a liquid crystal layer or OLED as a display function layer, an n-type polycrystalline silicon thin film transistor can be used as a driving transistor for applying a voltage (current) to the display function layer, and an n-type oxide semiconductor thin film transistor can be used as a The signal is sent to the switching transistor of this polysilicon thin film transistor.

As the drain electrode 26 and the source electrode 24 (source wiring 31), the same structure can be adopted. For example, multiple conductive layers can be used for the drain electrode 26 and the source electrode 24. For example, an electrode structure that holds aluminum, copper, or an alloy layer thereof with molybdenum, titanium, tantalum, tungsten, a conductive metal oxide film, or the like can be used. The drain electrode 26 and the source electrode 24 may be formed on the fourth insulating layer 14 first, and the channel layer 27 may be formed by stacking the two electrodes. The structure of the transistor may be a multi-gate structure such as a double gate structure.

The semiconductor layer or the channel layer can adjust the mobility or electron concentration in its thickness direction. The semiconductor layer or the channel layer may have a laminated structure of different oxide semiconductors. The minimum distance between the source electrode and the drain electrode The channel length of the transistor determined by the interval can be set to 10 nm or more and 10 μm or less, for example, 20 nm to 1 μm.

The third insulating layer 13 functions as a gate insulating film. As such an insulating film material, hafnium silicate (HfSiOx), silicon oxide, gallium oxide, aluminum oxide, silicon nitride, silicon nitride oxide, aluminum oxide nitride, gallium oxide, zinc oxide, hafnium oxide, cerium oxide Or an insulating film mixed with them. The cerium oxide system has a high dielectric constant, and the bond between cerium and oxygen atoms is strong. Therefore, it is preferable that the gate insulating film be a composite oxide containing cerium oxide. When cerium oxide is used as one of the oxides constituting the composite oxide, it is easy to maintain a high dielectric constant even in an amorphous state. Cerium oxide has oxidizing power. Therefore, the structure in which the oxide semiconductor and cerium oxide are in contact can avoid oxygen deficiency of the oxide semiconductor, and a stable oxide can be realized. The structure using nitride for the gate insulating film does not exhibit the effect as described above. In addition, the material of the gate insulating film may include lanthanum metal silicate represented by cerium silicate (CeSiOx).

The structure of the third insulating layer 13 may be a single-layer film, a mixed film, or a multilayer film. In the case of a mixed film or a multilayer film, a material selected from the above-mentioned insulating film materials can be used to form a mixed film or a multilayer film. The film thickness of the third insulating layer 13 is, for example, a film thickness selectable from the range of 2 nm or more and 300 nm or less. When the channel layer 27 is formed of an oxide semiconductor, the interface of the third insulating layer 13 in contact with the channel layer 27 can be formed in a state containing a lot of oxygen (film forming gas environment).

In the manufacturing process of the thin film transistor, the thin film transistor having a top gate structure can form a gate insulating film containing cerium oxide in an introduced gas containing oxygen after forming an oxide semiconductor. At this time, can The surface of the oxide semiconductor under the gate insulating film is oxidized, and the degree of oxidation of the surface can be adjusted. The formation step of the thin film transistor system gate insulating film having a bottom gate structure is performed before the step of the oxide semiconductor, so it is difficult to adjust the degree of oxidation of the surface of the oxide semiconductor. Compared with the case of the bottom gate structure, the thin film transistor with the top gate structure can promote the oxidation of the surface of the oxide semiconductor, and it is difficult to cause oxygen deficiency of the oxide semiconductor.

The plurality of insulating layers including the first insulating layer 11, the second insulating layer 12, the third insulating layer 13, and the underlying insulating layer of the oxide semiconductor (fourth insulating layer 14) can be formed using an inorganic insulating material or an organic insulating material . As the material of the insulating layer, silicon oxide, silicon oxynitride, or aluminum oxide can be used, and as the structure of the insulating layer, a single layer or a plurality of layers including the above materials can be used. It may be a structure in which a plurality of layers formed with different insulating materials are stacked. In order to obtain the effect of flattening the upper surface of the insulating film, acrylic resin, polyimide resin, benzocyclobutene resin, polyamide resin, etc. may be used for a part of the insulating layer. Low-dielectric materials (low-k materials) can also be used.

The gate electrode 25 is arranged on the channel layer 27 through the third insulating layer 13. The gate electrode 25 (gate wiring 10) can be formed in the same step using the same material as the above-mentioned common wiring 30 and having the same layer structure. In addition, the gate electrode 25 may be formed using the same material as the drain electrode 26 and the source electrode 24 described above, and having the same layer structure. When the gate electrode 25 is formed using multiple layers of conductive materials, a structure in which a copper layer or a copper alloy layer is sandwiched with a conductive metal oxide can be adopted.

The surface of the metal layer 5 exposed at the end of the gate electrode 25 can also be covered with a composite oxide containing indium. Alternatively, the entire gate electrode 25 may be covered with a nitride such as silicon nitride or molybdenum nitride so as to include the end of the gate electrode 25. Alternatively, an insulating film having a thickness greater than 50 nm and having the same composition as the above-mentioned gate insulating film can be laminated.

As a method of forming the gate electrode 25, before the gate electrode 25 is formed, only the third insulating layer 13 located directly above the channel layer 27 of the active element 28 may be dry-etched or the like, and the third insulating layer 13 may be The thickness is reduced.

An oxide semiconductor having different electrical properties may be further inserted at the interface of the gate electrode 25 in contact with the third insulating layer 13. Alternatively, the third insulating layer 13 may be formed of an insulating metal oxide layer containing cerium oxide or gallium oxide.

Specifically, in order to suppress the noise caused by the video signal supplied to the source wiring 31 from passing to the common wiring 30, the third insulating layer 13 must be thickened. On the other hand, the third insulating layer 13 has a function as a gate insulating film between the gate electrode 25 and the channel layer 27, and an appropriate film thickness considering the switching characteristics of the active element 28 is required. In this way, in order to realize the opposite two functions, the third insulating layer located directly above the channel layer 27 will be maintained under the film thickness of the third insulating layer 13 substantially maintained between the common wiring 30 and the source wiring 31 The thickness of 13 is reduced, so that the noise caused by the image signal supplied to the source wiring can be suppressed from being transmitted to the common wiring 30, and the desired switching characteristics can be realized in the active device 28.

In addition, a light-shielding film may be formed under the channel layer 27. As the material of the light-shielding film, high melting point metals such as molybdenum, tungsten, titanium, and chromium can be used.

The gate wiring 10 is electrically connected to the active element 28. Specifically, the gate electrode 25 connected to the gate wiring 10 and the channel layer 27 of the active element 28 face each other through the third insulating layer 13. Based on the scanning signal supplied from the video signal control unit 121 to the gate electrode 25, the active element 28 is switched and driven.

The source wiring 31 is given a voltage as a video signal from the video signal control unit 121. The source wiring 31 is given a video signal with a positive or negative voltage of, for example, ±2.5V to ±5. As the voltage applied to the common electrode 17, for example, it can be set within a range of ±2.5V that varies by amplitude inversion. In addition, the potential of the common electrode 17 may be set to a constant potential in the range from the critical value Vth of liquid crystal driving to 0V. When this common electrode is applied to constant-potential driving described later, it is desirable to use an oxide semiconductor for the channel layer 27. The channel layer composed of an oxide semiconductor has a high electrical withstand voltage. By using an oxide semiconductor transistor, a high driving voltage exceeding a range of ±5 V can be applied to the electrode portion 17A to increase the response of the liquid crystal at high speed. Change. For liquid crystal driving, various driving methods such as amplitude inversion driving, column inversion (vertical line) inversion driving, horizontal line inversion driving, and dot inversion driving can be applied. The liquid crystal drive of this embodiment will be described later with reference to FIG. 14.

When a copper alloy is used as a part of the structure of the gate electrode 25, a metal element or a semimetal element within a range of 0.1 at% or more and 4 at% or less relative to copper can be added. By adding an element to copper in this way, an effect capable of suppressing the migration of copper can be obtained. especially, It is preferable that the element which can be arranged in the lattice position of copper by substituting a part of copper atoms in the crystal (grain) of the copper layer and the precipitation at the crystal grain boundaries of the copper layer suppress copper. Elements that act as copper atoms near the crystal grains are added to the copper together. Alternatively, it is preferable to add an element heavier than copper atoms (larger atomic weight) to copper in order to suppress the action of copper atoms. In addition to this, it is preferable to select an additive element whose copper conductivity is difficult to decrease at an addition amount in the range of 0.1 at% to 4 at% relative to copper. In addition, in consideration of vacuum film formation such as sputtering, it is preferable that the film formation rate such as sputtering is close to copper. The technique of adding elements to copper as described above can also be applied if copper is replaced with silver or aluminum. In other words, silver alloy or aluminum alloy can be used instead of copper alloy.

An element that can be placed in the lattice position of copper by substituting a part of copper atoms in the crystals (grains) of the copper layer is added to copper, in other words, it is a metal or semimetal that forms a solid solution with copper at normal temperature Added to copper. Examples of metals that easily form solid solutions with copper include manganese, nickel, zinc, palladium, gallium, and gold (Au). An element that precipitates at the crystal grain boundaries of the copper layer to suppress the movement of copper atoms in the vicinity of the copper crystal grains is added to copper, in other words, a metal or semimetal that does not form a solid solution with copper near normal temperature is added. Various materials can be cited as metals or semi-metals that are difficult to form a solid solution with copper, or do not form a solid solution with copper. For example, high-melting-point metals such as titanium, zirconium, molybdenum, and tungsten; elements called semimetals such as silicon, germanium, antimony, and bismuth;

From a migration point of view, copper has problems with reliability. By adding the above-mentioned metal or semimetal to copper, the reliability surface can be supplemented. By adding the above metal or semimetal relative to copper at 0.1at% or more, the available To inhibit migration. However, when the above-mentioned metal or semimetal relative to copper is added at more than 4 at%, the deterioration of copper conductivity becomes significant, and the advantage of selecting copper or copper alloy cannot be obtained.

As the conductive metal oxide, for example, two or more composite oxides (mixed oxides) selected from indium oxide, tin oxide, zinc oxide, and antimony oxide can be used. To this composite oxide, a small amount of titanium oxide, zirconium oxide, aluminum oxide, magnesium oxide, and germanium oxide may be further added. The composite oxide of indium oxide and tin oxide is generally used as a low-resistance transparent conductive film called ITO. In the case of using a ternary composite oxide of indium oxide, zinc oxide, and tin oxide, the etching rate in wet etching can be adjusted by adjusting the mixing ratio of zinc oxide and tin oxide. In the three-layer structure using the ternary composite oxide of indium oxide, zinc oxide, and tin oxide to hold the alloy layer, the etching rate of the composite oxide and the etching rate of the copper alloy layer can be adjusted to enable the pattern of these three layers The width is approximately equal.

Generally, in order to perform gray-scale display, various voltages corresponding to the gray-scale display are applied to the source wiring, and the video signal is given to the source wiring at various timings. Noise caused by such an image signal is easily transmitted to the common electrode 17, which may lower the detection accuracy of touch sensing. Therefore, as shown in FIG. 5, by adopting a structure in which the distance W2 between the source wiring 31 and the touch sensing wiring 3 is increased, an effect that noise can be reduced can be obtained.

In this embodiment, as the active element 28, a transistor having a top gate structure can be used. It is also possible to replace the top gate structure with a transistor with a bottom gate structure, but in the case of a transistor with a top gate structure In this case, the position of the source wiring 31 in the Z direction can be separated from the touch sensing wiring 3. In other words, in the case of a transistor having a top gate structure, the source wiring can be separated from the space where capacitance is generated between the touch sensing wiring 3 and the common electrode 17. In this way, the source wiring is separated from the space where the capacitance is generated, so that the influence of noise on the touch signal detected between the touch sensing wiring 3 and the common electrode 17 can be reduced, that is, the wiring from the source The generated noise of various image signals gives the influence of touch signals. In this embodiment, it is important that the physical space between the touch sensing wiring 3 and the common electrode 17 does not include the source wiring 31 or the pixel electrode 20. In the following description, the physical space between the touch sensing wiring 3 and the common electrode 17 may be referred to as a touch sensing space. In addition, it is desirable to form a touch sensing space considering the distance W4 of the gate wiring 10 and the common wiring 30 (conductive wiring) illustrated in FIG. 13 together with the distance W2 described above. By obtaining the distance W4, it is possible to alleviate the influence of the noise caused by the gate signal supplied to the gate wiring 10 on the common wiring 30.

(Specific structure of the display device substrate 100)

Next, the specific structure of the display device substrate 100 will be described with reference to FIGS. 6 to 9. FIG. 6 is a plan view partially showing the liquid crystal display device LCD1 according to the first embodiment of the present invention, viewed from the observer side through the transparent substrate 21.

FIG. 7 is a partial cross-sectional view of the display device substrate 100 according to the first embodiment of the present invention, taken along the line F-F' shown in FIG. 6. FIG. 8 is a cross-sectional view partially showing the display device substrate 100 according to the first embodiment of the present invention, illustrating the terminals of the touch sensing wiring 3 Sectional view of section 34. FIG. 9 is a cross-sectional view partially showing the display device substrate 100 according to the first embodiment of the present invention, and a cross-sectional view illustrating the terminal portion 34 of the touch sensing wiring 3.

As shown in FIG. 6, on the array substrate 200 shown in FIG. 2, the display device substrate 100 is laminated through the liquid crystal layer. Thereby, the liquid crystal display device LCD1 in which the display device substrate 100 is bonded to the array substrate 200 through the liquid crystal layer 300 can be obtained.

In FIG. 6, the source wiring 31 and the common wiring 30 constituting the array substrate 200 are shown, and other members (electrodes, wiring, active elements, etc.) constituting the array substrate 200 are omitted.

The display device substrate 100 includes a color filter 51 (RGB), a touch sensing wiring 3, and a black matrix BM. The black matrix BM has a lattice pattern with a plurality of pixel openings. A red filter (R), a green filter (G), and a blue filter (blue) constituting the color filter 51 are provided in each of the plurality of pixel openings. The black matrix BM has an X-direction extending portion extending in the X-direction and a Y-direction extending portion extending in the Y-direction, and is formed of the material constituting the black layer 8 described above. In addition, the Y-direction extension corresponds to the black layer 8. The touch sensing wiring 3 is provided on the display device substrate 100 (see FIG. 7) so as to overlap with the Y-direction extending portion (part of the black matrix) of the black matrix BM.

In addition, the touch sensing wiring 3 is formed on the black matrix BM and extends in the Y direction. In the positional relationship of the display device substrate 100 and the array substrate 200 in a plan view, the touch sensing wiring 3 is arranged to overlap the source wiring 31, and the extending direction of the touch sensing wiring 3 is relative to the common wiring 30 The direction of extension is orthogonal.

As shown in FIG. 7, on the black layer 8 constituting the black matrix BM, a three-layer touch sensing of a first conductive metal oxide layer, a copper alloy layer, and a second conductive metal oxide layer is stacked Wiring 3.

As a material of the conductive metal oxide layer, a conductive metal oxide based on indium oxide or tin oxide can be used. For example, a composite oxide in which zinc oxide, tin oxide, titanium oxide, zirconium oxide, magnesium oxide, aluminum oxide, germanium oxide, gallium oxide, cerium oxide, antimony oxide, or the like is added to indium oxide can be used. At least, in the case of using a mixed oxide system of mixed zinc oxide, the etching rate in wet etching can be adjusted according to the addition amount of zinc oxide, antimony oxide, and gallium oxide relative to indium oxide.

The touch sensing wiring or conductive wiring (commonly formed on the array substrate 200) of the three-layer structure in which the first conductive metal oxide layer, the copper alloy layer, and the second conductive metal oxide layer are formed as described above In the case of the wiring 30), it is important to adjust the etching rate of the conductive metal oxide and the copper alloy, and to perform etching with approximately the same width. The binary material of indium oxide and zinc oxide is used as the main material, and other necessary elements, such as other metal oxides that can improve conductivity or reliability, are added to the main material to achieve the above three-layer structure. Wiring.

For example, composite oxides based on composite metal oxides such as indium oxide-zinc oxide-tin oxide have high conductivity, and also have strong adhesion to copper alloys, color filters, and glass substrates. In addition, the composite metal oxide may be a hard ceramic, and in the electrical structure, good ohmic contact can be obtained. If the conductivity of such a composite oxide When the conductive metal oxide layer is applied to the above three-layer structure of the first conductive metal oxide layer, the copper alloy layer, and the second conductive metal oxide layer, for example, extremely strong electrical properties can be performed on the glass substrate Build.

As shown in FIG. 7, on the black matrix BM, a second conductive metal oxide layer including a ternary mixed oxide film (conductive metal oxide layer) of indium oxide, zinc oxide, and tin oxide is continuously formed 4. The metal layer 5 and the first conductive metal oxide layer 6 similar to the second conductive metal oxide layer 4 can form three layers. As a film forming apparatus, for example, a sputtering apparatus is used, and continuous film forming is performed while maintaining a vacuum gas environment.

For example, in the second conductive metal oxide layer 4 and the first conductive metal oxide layer 6, the composition of the respective metal layers of indium oxide, zinc oxide, tin oxide, and copper alloy is as follows. In any case, the atomic percentage of the metal element in the mixed oxide (the oxygen element is not counted but only the metal element is counted. Hereinafter, marked as at%).

90：8：2 ‧The first conductive metal oxide layer; In: Zn: Sn

90: 8: 2

91：7：2 ‧The second conductive metal oxide layer; In: Zn: Sn

91: 7: 2

98.6：1.0：0.4 ‧Metal layer; Cu: Zn: Sb

98.6: 1.0: 0.4

The amount of indium (In) contained in the first conductive metal oxide layer 6 and the second conductive metal oxide layer 4 must be more than 80 at%. The amount of indium (In) is preferably more than 80 at%. The amount of indium (In) is more preferably more than 90at%. When the amount of indium (In) is less than 80 at%, the specific resistance of the conductive metal oxide layer formed becomes large, which is not good. If the amount of zinc (Zn) exceeds 20 at%, the alkali resistance of the conductive metal oxide (mixed oxide) decreases, which is not good.

The amount of zinc (Zn) contained in the first conductive metal oxide layer 6 and the second conductive metal oxide layer 4 must be set to be greater than the amount of tin (Sn). If the tin content exceeds the zinc content, the wet etching in the subsequent steps causes hindrance. In other words, the metal layer of copper or copper alloy becomes easier to be etched than the conductive metal oxide layer, and the widths of the first conductive metal oxide layer 6, the metal layer 5, and the second conductive metal oxide layer 4 become It’s easy to make a difference.

The amount of tin (Sn) contained in the first conductive metal oxide layer 6 and the second conductive metal oxide layer 4 is preferably within a range of 0.5 at% or more and 6 at% or less. In comparison with the indium element, by adding 0.5at% or more and 6at% or less of tin to the conductive metal oxide layer, the ternary mixed oxide film of indium, zinc, and tin (conductive Composite oxide layer). If the amount of tin exceeds 6 at%, zinc is added to the conductive metal oxide layer, so the specific resistance of the ternary mixed oxide film (conductive composite oxide layer) becomes excessive. By adjusting the amount of zinc and tin within the above range (0.5at% or more and 6at% or less), or by adjusting the film forming conditions or annealing conditions, etc., the specific resistance can be mixed with a single-layer film of an oxide film In terms of specific resistance, it is included in a small range of about 3×10 ^-4 Ωcm or more and 5×10 ^-4 Ωcm or less. In the above mixed oxide, other elements such as titanium, zirconium, magnesium, aluminum, and germanium can also be added in small amounts.

The black matrix BM has a frame area surrounding the matrix area (rectangular display area and display screen) in the display surface (display section 110). It is preferable to form the touch sensing wiring 3 on the transparent substrate 21 so as to extend from the frame area toward the outside of the transparent substrate 21 The touch sensing wiring 3 outside the frame area forms a terminal portion 34. In this case, the terminal portion 34 of the touch sensing wiring 3 is provided at a position extending from the frame area without overlapping with the black matrix BM. In this structure, the terminal portion 34 used for construction can be directly formed on the glass surface of the transparent substrate 21 of the glass plate.

FIG. 8 is a cross-sectional view of the touch sensing wiring 3 extending from the black matrix BM of the frame area toward the outside of the transparent substrate 21, along the X direction. The terminal portion 34 of the touch sensing wiring 3 is directly arranged on the transparent substrate 21 of the glass plate. FIG. 9 is a cross-sectional view showing the terminal portion 34, along the Y direction.

The shape of the terminal portion in plan view is not limited to FIG. 8 or FIG. 9. For example, after covering the terminal portion 34 with the transparent resin layer 16, the upper portion of the terminal portion 34 is removed by dry etching or the like to form the terminal portion 34 having a circular or rectangular shape, and the conductive metal oxide layer is placed on the terminal portion The surface of 34 is exposed. In this case, it is possible to transfer the conduction from the display device substrate 100 to the array substrate 200 in the thickness direction of the sealing portion in the sealing portion where the display device substrate 100 and the array substrate 200 are bonded, or inside the liquid crystal cell (transfer). The conductor selected from the anisotropic conductive film, the tiny metal ball, or the resin ball covered with the metal film is arranged in the sealing portion, so that the display device substrate 100 and the array substrate 200 can be conducted.

In the conduction structure between the display device substrate 100 and the array substrate 200, three layers of the first conductive metal oxide layer 6, the copper alloy layer (metal layer 5), and the second conductive metal oxide layer 4 are not used It is only arranged on the display device substrate 100, preferably in the same way, the first The terminal portion formed by three layers of the conductive metal oxide layer, the copper alloy layer, and the second conductive metal oxide layer is formed on the array substrate 200. In this way, the terminal formed on the array substrate 200 can be used as a terminal for transferring conduction to the display device substrate 100. Specifically, either the structure of the layer constituting the conductive layer formed on the gate wiring 10 of the array substrate 200 or the structure of the layer constituting the conductive layer of the source wiring 31 is set as the first conductivity Three-layer structure of a conductive metal oxide layer, a copper alloy layer, and a second conductive metal oxide layer. With this, it is possible to form, on the array substrate 200, the return wiring or terminal portion for conduction between the display device substrate 100 and the array substrate 200.

(Liquid crystal layer 300)

Returning to FIG. 3, the liquid crystal layer 300 (display function layer) will be described.

The liquid crystal layer 300 includes liquid crystal molecules 39 having positive dielectric anisotropy. The initial alignment of the liquid crystal molecules is parallel to the substrate surface of the display device substrate 100 or the array substrate 200. The liquid crystal driving of the first embodiment using the liquid crystal layer 300 applies a driving voltage to the liquid crystal molecules across the liquid crystal layer in a plan view, and therefore may be referred to as a transverse electric field method. The operation of the liquid crystal molecules 39 will be described later with reference to FIGS. 15 and 16. The liquid crystal constituting the liquid crystal layer 300 may be a liquid crystal having a negative dielectric anisotropy or a liquid crystal having a positive dielectric anisotropy. Preferably, the liquid crystal or the alignment film used in the liquid crystal display device, or even the transparent resin layer provided in the display device substrate has a high resistivity, and the resistivity of these members is preferably 1×10 ¹³ Ω‧cm or more.

(Manufacturing method of liquid crystal display device LCD1)

Next, a method of manufacturing the liquid crystal display device LCD1 including the array substrate 200 having the pixel structure shown in FIGS. 2 to 5 will be described using FIGS. 10 to 13.

First, the transparent substrate 22 is prepared, and the fourth insulating layer 14 is formed so as to cover the surface of the transparent substrate 22.

Next, as shown in FIG. 10, the channel layer 27 constituting the active element 28 is formed on the fourth insulating layer 14. As the material of the channel layer 27, an oxide semiconductor can be used. In this embodiment, the channel layer 27 is patterned so that one channel layer 27 is arranged in one pixel. In Fig. 10, broken lines 131 and 90 are shown. The dotted line 131 indicates the position of the source wiring formed on the fourth insulating layer 14 after the channel layer 27 is formed. The dotted line 90 indicates the position of the gate wiring formed on the third insulating layer 13 after the source wiring 31 is formed.

Next, as shown in FIG. 11, the source electrode 24 and the drain electrode 26 are formed on the channel layer 27, and at the same time, the source wiring 31 electrically connected to the source electrode 24 is formed. The source wiring 31 has a linear pattern extending in the Y direction.

Next, a third insulating layer 13 is formed on the transparent substrate 21, that is, on the fourth insulating layer 14 so as to cover the channel layer 27, the source electrode 24, the drain electrode 26, and the source wiring 31. This third insulating layer 13 has a function as an interlayer insulating film between two wiring layers, and a function as a gate insulating film.

Next, as shown in FIG. 12, after the third insulating layer 13 is formed, the gate electrode 25 is formed on the third insulating layer 13 so as to coincide with the formation position of the channel layer 27. In addition, simultaneously with the formation of the gate electrode 25 Ground, the gate wiring 10 electrically connected to the gate electrode 25 and the common wiring 30 are formed. The gate electrode 25, the gate wiring 10, and the common wiring 30 are conductive layers made of a conductive material as described above, and are formed in the same step.

Next, the second insulating layer 12 is formed on the transparent substrate 22, that is, on the third insulating layer 13 so as to cover the gate electrode 25, the gate wiring 10, and the common wiring 30. After the second insulating layer 12 is formed, a transparent conductive film is formed on the entire surface of the second insulating layer 12.

Thereafter, by patterning the transparent conductive film, the pixel electrode 20 is formed for each pixel as shown in FIG. 13. When the pixel electrode 20 is patterned, a through hole 20S is also formed. That is, the through hole 20S becomes an opening from which the transparent conductive film is removed.

FIG. 13 shows a structure in which the second insulating layer 12 covering the active element 28, the source wiring 31, the gate wiring 10, the common wiring 30, and the like is formed. The pixel electrode 20 is formed on the second insulating layer 12 by patterning. The pixel electrode 20 is electrically connected to each source electrode 26 of the active device 28 through the contact hole 29. In addition, the diameter of the through hole 20S formed in the pixel electrode 20 is larger than the diameter of the contact hole H formed in the subsequent step. The through hole 20S has a sufficient size (diameter) that does not cause leakage of the common electrode 17 and the common wiring 30 inside the contact hole H. In FIG. 13, the distance W4 between the common wiring 30 and the gate wiring 10 is shown. Since the distance W4 is obtained, the noise caused by the common wiring 30 hardly affects the structure of the gate wiring 10.

Next, on the transparent substrate 22, that is, on the second insulating layer 12, the first insulating layer 11 is formed. With this, the first insulating layer 11 is buried The through hole 20S covers the entire surface of the pixel electrode 20. After that, contact holes H are formed in the first insulating layer 11 and the second insulating layer 12 at positions corresponding to the through holes 20S. By etching the first insulating layer 11 and the second insulating layer 12, a plurality of contact holes H are formed on the entire surface of the array substrate 200 at a time.

After that, a transparent conductive film of the constituent material of the common electrode 17 is formed on the first insulating layer 11 so as to cover the contact hole H. Thereafter, by patterning the transparent conductive film, the electrode portion 17A shown in FIG. 4B is formed on the first insulating layer 11, and the conductive connection portion 17B is buried inside the contact hole H to form the common electrode 17. Thereby, the common electrode 17 and the common wiring 30 are conducted. Through the above steps, the array substrate 200 shown in FIG. 2 is obtained.

In the example shown in FIG. 2, the common electrode 17 is formed on the first insulating layer 11 formed so as to cover the pixel electrode 20. In addition, in one pixel, two common electrodes 17 having a stripe pattern shape are arranged in the longitudinal direction of the pixel. The pattern shape or number of the common electrode 17 is not limited thereto, and can be increased or decreased according to the pixel size or pixel size. The common electrode 17 is formed of a transparent conductive film such as ITO. In addition, the common electrode 17 is electrically connected to the common wiring 30 through the contact hole H at the center of the pixel in the longitudinal direction. The portion where the common electrode 17 overlaps the pixel electrode 20 can be used as an auxiliary capacitor when performing liquid crystal display.

If the manufacturing method of the above-mentioned liquid crystal display device LCD1 is used, even if the source wiring or the gate wiring for driving the active element are provided together on one array substrate, there is no need to By setting jumper wires or bypass channels, the liquid crystal display device LCD1 can be manufactured at low cost.

(Time-sharing of LCD driver and touch sensor driver)

FIG. 14 is a timing chart showing an example of time-division driving applicable to liquid crystal driving and touch sensing driving in the first embodiment and the embodiments described later.

In addition, regarding the ordinal representation of the first pulse signal or the second pulse signal described below, for example, it is assumed that an odd number of pulse signals Vc supplied as a clock frequency is called a first pulse signal, and an even number is called a second pulse. The signal is just a continuous signal, not a specific pulse signal Vc.

The display period shown in FIG. 14 is a display period in which one frame is 60 Hz, for example. In this one-frame period, for example, one display unit period of pixels includes a white display period and a black display period.

By inputting the first pulse signal of the clock signal, it is displayed in white. Specifically, with the input of the first pulse signal, the image signal is supplied to the source wiring 31, and the liquid crystal driving voltage Vd is supplied to the pixel electrode 20 through the drain electrode 26. The liquid crystal driving voltage Vd is held between the pixel electrode 20 and the common electrode 17 to drive the liquid crystal layer. Compared with an active device using a polycrystalline silicon semiconductor as a channel layer, an active device (thin film transistor) 28 series liquid crystal using an oxide semiconductor as a channel layer has a high driving voltage holding capability and can maintain high transmittance of each pixel for a long period of time.

Then, by inputting the second pulse signal, the white display shifts to the black display. The black display, for example, can be held between the pixel electrode 20 and the common electrode 17 by using the second pulse signal as a trigger The voltage is set to 0V or ground potential to achieve. For example, it becomes possible to accelerate the return to 0V by supplying a voltage of the opposite polarity to the image signal supplied to the source wiring during the white display with an application time corresponding to the width of the aforementioned pulse signal. The voltage of this opposite polarity may be a low voltage near the threshold voltage Vth for liquid crystal driving. In order to shift to the black display, it is preferable to ground the gate wiring. In the case of using a polycrystalline silicon semiconductor as the active element of the channel layer, after the second pulse signal is input, only the gate wiring 10 or the source wiring 31 may be grounded. In addition, black display means that the liquid crystal molecules of the liquid crystal layer return to the initial alignment state and the black state under orthogonal polarization.

The touch sensing period T _touch is set to a white display stabilization period Wr with stable transmittance or a black display stabilization period Er, during which touch sensing can be performed. While supplying the image signal or the gate signal to the source wiring 31 or the gate wiring 10, for example, within the application time Dt of the applied voltage Vd, the touch sensing wiring 3 becomes easily accidentally obtained from the source wiring or active The noise generated by the component is not good.

The liquid crystal display device of the embodiment of the present invention can employ various liquid crystal driving methods such as amplitude inversion driving, column inversion driving (vertical line inversion driving), horizontal line inversion driving, and dot inversion driving. According to the liquid crystal driving method, for example, the timing of the touch sensing period described below can be adopted.

(1) Timing after image writing based on multiple pixels such as 1 pixel or 2 pixels (after image display based on the display unit period)

(2) Timing after writing a vertical line of image

(3) Timing after writing a horizontal line of image

(4) Timing after writing based on 1 or 1/2 image

The period "after image writing" of (1) to (4) is synonymous with the white display stable period Wr shown in FIG. In addition, the "after image writing" in (1) to (4) above can be replaced with the black display stable period Er shown in FIG. 14. As described above, the touch sensing period may be set in two periods of the white display stabilization period Wr and the black display stabilization period Er.

As shown in the timing chart of FIG. 14, during the black display stable period Er, a high-frequency touch sensing driving voltage V _{touch is} applied to the touch driving wiring (touch sensing wiring 3 or common wiring 30 described later) .

In addition, during the black display stabilization period Er, the light emission of the backlight unit BU such as LED can be stopped, and the influence of noise caused by driving of the backlight unit BU can be eliminated. The black display stabilization period can also be used as "black insertion" for reducing color cast in 3D display (stereoscopic image display).

During the touch sensing period T _touch , the touch driving voltage can be applied to either the touch sensing wiring 3 or the common wiring 30. In other words, when the touch sensing wiring 3 functions as a drive electrode, the common electrode 17 can function as a detection electrode. Conversely, when the touch sensing wiring 3 functions as a detection electrode, the common electrode 17 can function as a drive electrode. That is, the functions of the drive electrode and the detection electrode can be exchanged for the touch sensing wiring 3 and the common electrode 17.

In addition, in the time-division driving of liquid crystal driving and touch driving, the rectangular wave of the touch driving voltage V _touch is usually applied to any one of the touch sensing wiring 3 and the common electrode 17, only in When a pulse with a clock frequency (first pulse signal, second pulse signal) is applied, the touch detection signal is not detected. That is, in essence, a method of dividedly driving may be adopted.

(Transistor using oxide semiconductor as channel layer)

For example, if an oxide semiconductor such as IGZO with good memory or IGAO which replaces zinc oxide with antimony oxide is used as the transistor (active element) of the channel layer 27, the common electrode 17 may be omitted A constant voltage at a constant voltage (constant potential) drives the required storage capacitor. The transistor system using IGZO or IGAO as the channel layer 27 is different from the transistor using a silicon semiconductor, and since the leakage current is extremely small, it is possible to omit the transfer circuit including the latch portion as described in Patent Document 4 of the prior art document, for example. A simple wiring structure is used. In addition, in the liquid crystal display device LCD1 using the array substrate 200 including the transistor using an oxide semiconductor such as IGZO as the channel layer, since the leakage current of the transistor is small, the voltage can be maintained after the liquid crystal driving voltage is applied to the pixel electrode 20 , The transmittance of the liquid crystal layer 300 can be maintained.

When an oxide semiconductor such as IGZO is used for the channel layer 27, the electron mobility in the active element 28 is high, for example, the driving voltage corresponding to the required image signal can be applied in a short time of less than 2msec (millisecond) Apply to the pixel electrode 20. For example, one frame of double-speed driving (in the case of 120 frames per second) is about 8.3 msec, for example, 6 msec can be allocated to touch sensing. The thin film transistor using an oxide semiconductor such as IGZO as the channel layer 27 has a high withstand voltage. Therefore, for example, the response of the liquid crystal can be improved by using a high voltage of 5 V or more as the liquid crystal driving voltage.

When the common electrode 17 having a transparent electrode pattern is at a constant potential, the liquid crystal drive and the touch electrode drive may not be driven in a time-sharing manner. The driving frequency of the liquid crystal can be different from that of the touch metal wiring. For example, the use of an oxide semiconductor such as IGZO for the active element 28 of the channel layer 27 is different from a transistor using a polysilicon semiconductor that must maintain transmittance (or hold voltage) after applying a liquid crystal driving voltage to the pixel electrode 20 There is no need to refresh the image (write the image signal again) in order to maintain the transmittance, and there is less flicker. This makes it possible to drive at a low frequency or drive with low power consumption in the liquid crystal display device LCD1 using an oxide semiconductor such as IGZO.

By using the aforementioned two-layer structure TFT array, it becomes possible to drive with low power consumption in a wide area from a low frequency to a high frequency.

Oxide semiconductor systems such as IGZO have high voltage resistance, so they can drive liquid crystals at high speeds at high speeds, and can be used for 3D video display that can display in 3D. As described above, the active element 28 using an oxide semiconductor such as IGZO for the channel layer 27 has high memory, and therefore, for example, even if the liquid crystal driving frequency is set to a low frequency of about 0.1 Hz or more and 30 Hz or less, it is difficult to generate flicker (flicker, display flashing) advantages. Using the active element 28 with IGZO or IGAO as the channel layer, by performing the dot inversion drive based on the low frequency together with the touch drive based on the frequency different from the dot inversion drive, it is possible to obtain high power with low power consumption Picture quality image display and high-precision touch sensing.

In addition, as described above, the active element 28 using the oxide semiconductor for the channel layer 27 has a small leakage current, and therefore can maintain the driving voltage applied to the pixel electrode 20 for a long time. The wiring resistance is smaller than aluminum wiring The copper wiring forms the source wiring 31 or the gate wiring 10 (auxiliary capacitor line) of the active element 28, etc., and further uses IGZO or IGAO that can be driven in a short time as an active element, so that it becomes possible to fully set up for touch sensing Measured scanning period. That is, the driving time of the liquid crystal and the like can be shortened by applying an oxide semiconductor such as IGZO to the active device. In the image signal processing of the entire display screen, the time applied to touch sensing is sufficiently sufficient. With this, it is possible to detect the change in capacitance generated with high accuracy.

In addition, by using an oxide semiconductor such as IGZO as the channel layer 27, the influence of coupling noise under dot inversion driving or column inversion driving can be approximately eliminated. This is because the active element 28 using an oxide semiconductor can apply the voltage corresponding to the image signal to the pixel electrode 20 in a very short time (for example, 2 msec), and also keeps the memory of the pixel voltage after the image signal is applied The performance is high, and no new noise is generated during the retention period in which the memory is utilized, which can reduce the influence on the touch sensing.

As the oxide semiconductor, an oxide semiconductor containing two or more kinds of metal oxides among indium, gallium, zinc, tin, aluminum, germanium, antimony, and cerium can be used.

An oxide semiconductor such as IGZO or IGAO has a high energy gap. The atomic ratios of gallium and zinc of indium (In), gallium (Ga), and zinc (Zn) contained in the oxide semiconductor film when the number of indium atoms is 1 can be set to 1 to 5, respectively. The melting points of metal oxides as indium oxide, gallium oxide, and zinc oxide are in the range of about 1700°C to 2200°C, respectively. For example, antimony oxide or bismuth oxide can be added to the above indium oxide, gallium oxide, Compound oxide of zinc oxide. In addition, in the composite oxide, antimony oxide or bismuth oxide may be used instead of gallium oxide or zinc oxide.

The concentration of metal elements such as indium or gallium in the thickness direction of the oxide semiconductor can be changed. For example, the amount of gallium oxide in the oxide semiconductor can be increased near the interface between the oxide semiconductor and the insulating layer, and the amount of indium oxide can be increased in the central portion in the film thickness direction. The concentration gradient of each metal element may exist in the thickness direction of the oxide semiconductor, and the carrier mobility in the thickness direction of the oxide semiconductor may vary.

(LCD alignment and LCD driver)

15 and 16 are plan views partially showing pixels of the liquid crystal display device LCD1 according to the first embodiment of the present invention. In order to easily understand and explain the alignment of the liquid crystal molecules 39, the alignment state of the liquid crystal in one pixel is displayed. FIG. 15 is a plan view partially showing the pixels of the liquid crystal display device LCD1, and showing the alignment state (initial alignment state) of the liquid crystal in one pixel. FIG. 16 is a plan view partially showing the pixels of the liquid crystal display device LCD1, and a plan view showing the liquid crystal driving operation when a liquid crystal driving voltage is applied between the pixel electrode 20 and the common electrode 17.

In the examples shown in FIGS. 15 and 16, the pixel electrode 20 is formed in a rectangular shape, and the longitudinal direction of the pixel electrode 20 coincides with the Y direction. The alignment treatment is applied to the alignment film so that the liquid crystal molecules 39 of the liquid crystal layer 300 are inclined at an angle θ with respect to the extending direction (Y direction) of the rectangular pixel electrode 20.

In particular, in this embodiment, each pixel is divided into two regions, that is, each pixel has an upper region Pa (first region) and a lower region Pb (second region). Upper area Pa and lower area Pb They are arranged in line symmetry with respect to the pixel center CL (a center line parallel to the X direction). The upper region Pa and the lower region Pb give the liquid crystal molecules 39 of the liquid crystal layer 300 a pretilt at an angle θ with respect to the Y direction. In the upper region Pa, the liquid crystal molecules 39 are given a pretilt at a clock angle θ with respect to the Y direction. In the lower region Pb, the liquid crystal molecules 39 are given a pretilt at a counterclockwise angle θ with respect to the Y direction. As the alignment treatment of the alignment film, light alignment treatment or rubbing treatment can be used. There is no need to specify the angle θ, for example, the angle θ may be set in the range of 3° to 15°.

In this way, the liquid crystal molecules 39 that are initially aligned are applied. When a voltage is applied between the pixel electrode 20 and the common electrode 17, a fringe electric field is generated between the pixel electrode 20 and the common electrode 17 as shown by the arrow in FIG. 16, and the liquid crystal molecules 39 aligns along the direction of the fringe electric field, driving liquid crystal molecules 39. More specifically, as shown in FIG. 26, a fringe electric field is generated from the pixel electrode 20 toward the common electrode 17, and the liquid crystal molecules 39 are driven along the fringe electric field and rotate in a plan view.

FIG. 26 is a partial cross-sectional view of the liquid crystal display device LCD1, showing the liquid crystal driving operation when a liquid crystal driving voltage is applied between the common electrode 17 and the pixel electrode 20. The liquid crystal driving method called FFS drives the liquid crystal molecules 39 by the electric field generated between the common electrode 17 and the pixel electrode 20, in particular, the electric field generated at the end of the electrode called the edge. As shown in FIG. 26, the liquid crystal molecules 39 in a part R1 in the thickness direction of the liquid crystal layer 300 rotate, and the liquid crystal molecules 39 mainly contribute to the change in transmittance. As a result, the transmittance in the vertical direction viewed from the observer can fully utilize the thickness direction of the liquid crystal layer 300 compared to a liquid crystal display device driven by a horizontal electric field such as FFS. Liquid crystal display devices driven by a vertical electric field such as VA of liquid crystal molecules can achieve high transmittance. Nevertheless, the liquid crystal display device driven by a transverse electric field such as FFS has such a characteristic that the viewing angle is wide. Therefore, from the viewpoint of this characteristic, the liquid crystal display device LCD1 of the present embodiment adopts a transverse electric field driving method.

FIG. 30 is a cross-sectional view showing a conventional liquid crystal display device 250, and a schematic diagram showing an equipotential line L2 when a liquid crystal driving voltage is applied. When the transparent electrode or the conductive film is not present on the transparent substrate 215 side, the equipotential line L2 penetrates through the transparent resin layer 213, the color filter 214, and the transparent substrate 215 and extends above. When the equipotential line L2 is extended in the thickness direction of the liquid crystal layer 206, the effective thickness of the liquid crystal layer 206 is ensured to some extent, so the original transmittance of the liquid crystal display device 250 of the horizontal electric field driving method can be ensured.

FIG. 31 is a cross-sectional view of a conventional liquid crystal display device 250A, which shows a case where the counter electrode 221 is provided between the liquid crystal layer 206 and the transparent resin layer 213 in addition to the above-described structures of the liquid crystal display device 250. In this case, the equipotential line L3 does not penetrate the counter electrode 221, so the shape of the equipotential line L3 is deformed by the shape of the aforementioned equipotential line L2. At this time, the effective thickness of the liquid crystal layer 206 is thinner than the effective thickness of the liquid crystal layer 206 of the liquid crystal display device 250, and the brightness (transmittance) of the liquid crystal display device 250A is greatly reduced.

The liquid crystal display device LCD1 of this embodiment is different from the conventional liquid crystal display device shown in FIGS. 30 and 31. In the liquid crystal display device LCD1 of this embodiment, the common electrode 17 is formed above the pixel electrode 20, and the potential of the common electrode 17 is maintained. At 0V, a voltage is applied between the pixel electrode 20 and the common electrode 17 to generate a fringe electric field from the pixel electrode 20 toward the common electrode 17, and the liquid crystal molecules 39 are driven by the fringe electric field.

(Touch sensing driver)

FIGS. 17 and 18 show that in the liquid crystal display device LCD1 according to the first embodiment of the present invention, the touch sensing wiring 3 functions as a touch drive electrode, and the common electrode 17 functions as a touch detection electrode. Structure in case of function.

Based on the structures shown in FIGS. 17 and 18, the following description will be made.

In addition, as described above, the roles of the touch drive electrode and the touch detection electrode can be exchanged.

FIG. 17 is a schematic cross-sectional view showing a state where an electric field is generated between the touch sensing wiring and the common electrode, and FIG. 18 is a view showing the electric field when a pointer such as a finger touches or approaches the surface of the display device substrate 100 on the observer side The cross-sectional view of the change of the generation state.

In FIGS. 17 and 18, the touch sensing technique using the touch sensing wiring 3 and the common electrode 17 will be described. FIGS. 17 and 18 show the first insulating layer 11 and the common electrode 17 that constitute the array substrate 200 and the display device substrate 100 for easy understanding and description of touch sensing driving, and other structures are omitted.

As shown in FIGS. 17 and 18, the touch sensing wiring 3 and the common electrode 17 face each other in an oblique direction inclined with respect to the thickness direction of the liquid crystal layer 300. Therefore, it is possible to easily increase the contrast of the detection signal with respect to the change in the state of the obliquely generated electric field (contrast), an effect that can improve the S/N ratio of touch sensing (the effect of improving the S/N ratio) can be obtained. In addition, in the arrangement in which the touch sensing wiring 3 and the common electrode 17 are opposed to each other in an oblique direction in this way, the overlapping portion where the touch sensing wiring 3 and the common electrode 17 overlap is not formed in a plan view, so it can be greatly Reduce parasitic capacitance. In addition, the structure in which the touch detection electrode and the touch drive electrode overlap in the vertical direction of the thickness is difficult to change the capacitance in the portion where the touch detection electrode and the touch drive electrode overlap each other, so it is difficult to sense the touch The S/N ratio provides contrast. For example, in the case where the touch detection electrode and the touch drive electrode are in a parallel positional relationship on the same plane, the capacitance tends to change unevenly depending on the position of the pointer such as a finger, which may cause false detection and reduced resolution Yu.

In the liquid crystal display device LCD1 of the embodiment of the present invention, as shown in FIG. 2 or FIG. 20, the common electrode 17 functions as a detection electrode and has a length EL. In a plan view, the common electrode 17 is parallel to the touch sensing wiring 3 functioning as a drive electrode, and the common electrode 17 having a length EL can sufficiently and uniformly ensure capacitance.

FIG. 17 schematically shows the generation of capacitance when the touch sensing wiring 3 functions as a touch drive electrode and the common electrode 17 functions as a touch detection electrode. A pulse-shaped write signal is supplied to the touch sensing wiring 3 at a predetermined frequency. The supply of the write signal can be performed by time-sharing of liquid crystal driving and touch driving. By writing the signal, the capacitance shown by the power line 33 (arrow) can be maintained between the grounded common electrode 17 and the touch sensing wiring 3.

As shown in FIG. 18, if a pointer such as a finger touches or approaches the surface of the display device substrate 100 on the observer side, the capacitance between the common electrode 17 and the touch sensing wiring 3 changes, and thus the capacitance changes. Detects the presence or absence of finger touches.

As shown in FIGS. 17 and 18, between the touch sensing wiring 3 and the common electrode 17, no electrode or wiring related to liquid crystal driving is provided. In addition, as shown in FIG. 3 or FIG. 5, the source wiring 31 is away from the touch sensing wiring 3 and the common electrode 17 (touch driving wiring and touch detection wiring). Therefore, a structure in which it is difficult to accidentally obtain noise related to liquid crystal driving can be realized.

For example, in a plan view, a plurality of touch sensing wires 3 are configured to extend in the first direction (for example, Y direction) and be arranged in the second direction (for example, X direction) at the same time. The plural common wirings 30 (conductive wirings) are located in the Z direction below the pixel electrode 20 in the array substrate 200, extend in the second direction (for example, X direction), and extend in the first direction ( For example, in the Y direction). The common electrode 17 is electrically connected to the common wiring 30, and changes in the capacitance between the common electrode 17 and the touch sensing wiring 3 are used to detect the presence or absence of touch.

In the liquid crystal display device LCD1 of the present embodiment, between the touch sensing wiring 3 and the common electrode 17, for example, a rectangular wave-shaped pulse signal is applied at a frequency of 500 Hz or more and 500 KHz or less. Generally, by the application of this pulse signal, the common electrode 17 of the detection electrode maintains a certain output waveform. If a pointer such as a finger touches or approaches the surface of the display device substrate 100 on the observer side, the output waveform of the common electrode 17 at that location changes, and it can be determined whether touch is present. Fingers and other indicators The distance from the display surface can be measured by the time from the proximity of the pointer to the contact (usually several hundreds of μsec or more and several msec or less), or the number of output pulses counted during this time. Stable touch detection can be performed by obtaining the integrated value of the touch detection signal.

It is not necessary to use all of the touch sensing wiring 3 and the common wiring 30 (or the common electrode connected to the conductive wiring) for touch sensing. Can drive reduction. Next, a case where the touch-sensing wiring 3 is driven to be reduced will be described. First, all the touch sensing wires 3 are divided into a plurality of groups. The number of groups is smaller than the number of all touch sensing wires 3. The number of wires forming one group is set to 6, for example. Here, among all the wirings (the number of wirings is 6), for example, 2 wirings are selected (the number of wirings is smaller than the number of all wirings, 2<6). In one group, the selected two wires are used for touch sensing, and the potential in the remaining four wires is set to a floating potential. The liquid crystal display device LCD1 has a plurality of groups, so that touch sensing can be performed according to the above-defined group of wiring functions. Similarly, the common wiring 30 can also be driven in a reduced manner.

The indicator used for touch is the case of a finger and the case of a pen, and the area or capacitance of the contacted or approached indicator is different. The number of wires reduced can be adjusted according to the size of such an indicator. For a pointer with a thin tip such as a pen or a needle tip, it is possible to reduce the number of wires and use a high-density touch-sensing matrix of wires. A matrix of high-density touch sensing wiring can also be used for fingerprint authentication.

In this way, the touch sensing drive is performed in groups, thereby reducing the number of wires used for scanning or detection, and thus can improve touch sensing speed. In addition, in the above example, the number of wires constituting one group is 6, but for example, it is also possible to form a group with more than 10 wires, and use the selected 2 wires in one group for touch sensing Measurement. That is, the number of wirings to be reduced (the number of wirings that become floating potentials) is increased, thereby reducing the density of the selection wiring used for touch sensing (density of the selection wiring to the total number of wirings), and the selection wiring is used for Scanning or detection, which helps reduce power consumption or improve touch detection accuracy. On the contrary, reducing the number of wires saved, increasing the density of the selection wiring used for touch sensing, and using the selection wiring for scanning or detection can be used for fingerprint authentication or input using a stylus pen, for example. During such a touch sensing period, the source wiring 31 or the gate wiring 10 can be grounded or opened (floating) to reduce the parasitic capacitance caused by these wirings.

It is also possible to perform touch sensing driving and liquid crystal driving in time-sharing. The frequency of touch driving can be adjusted in accordance with the required speed of touch input. The touch drive frequency can be higher than the liquid crystal drive frequency. The timing at which a pointer such as a finger touches or approaches the surface of the display device substrate 100 on the observer side is irregular and short, so it is desirable that the touch drive frequency is high.

There are several ways to make the touch drive frequency and the liquid crystal drive frequency different. For example, in a normally off liquid crystal drive, the backlight can also be turned off when the black display is off, and touch sensing is performed during the black display period (a period that does not affect the liquid crystal display) . In this case, various touch drive frequencies can be selected.

In addition, even in the case of using liquid crystal having a negative dielectric anisotropy, it is easy to select a touch driving frequency different from the liquid crystal driving frequency. In other words, as shown in FIGS. 17 and 18, the power lines 33 generated from the touch sensing wiring 3 toward the common electrode 17 act in the oblique direction or thickness direction of the liquid crystal layer 300, but if a negative medium is used, In the case of anisotropic liquid crystal, the liquid crystal molecules do not warp in the direction of the power line 33, so the influence on the display quality is reduced.

Furthermore, even when the wiring resistance of the touch sensing wiring 3 or the common wiring 30 is lowered and the touch driving voltage is lowered as the resistance is lowered, the touch driving frequency different from the liquid crystal driving frequency can be easily set. By using a metal or alloy with good conductivity such as copper or silver for the metal layer constituting the touch sensing wiring 3 or the common wiring 30, a low wiring resistance can be obtained.

In the case of a display device for 3D (stereoscopic image) display, in addition to the normal 2-dimensional video display, a plurality of video signals (for example, (The image signal for the right eye and the image signal for the left eye). Therefore, regarding the frequency of liquid crystal driving, for example, high-speed driving such as 240 Hz or 480 Hz and many image signals are required. In this case, the advantage obtained by making the frequency of touch driving different from the frequency of liquid crystal driving is large. For example, it becomes possible to perform high-speed and high-precision touch sensing in a game machine that performs 3D display using this embodiment. This embodiment is also particularly useful in displays with a high frequency of touch input such as fingers of game machines, ATMs and the like.

Represented by an animation display, pixel-based image signal replacement operations are frequently performed. The noise attached to these image signals is derived from the source wiring, so it is preferable to position the source wiring 31 in the thickness direction (Z direction) away from the touch sensing wiring 3 as in the embodiment of the present invention. According to the embodiment of the present invention, the touch driving signal is applied to the touch sensing wiring 3 located at a position away from the source wiring 31. Therefore, the patent that discloses a structure in which the touch driving signal is applied to the array substrate is provided on the array substrate Compared with literature 6, the influence of noise becomes less.

Generally speaking, the liquid crystal driving frequency is a driving frequency of 60 Hz or an integer multiple of this frequency. Generally, the touch sensing part is affected by noise accompanying the frequency of liquid crystal driving. In addition, a general household power supply is an AC power supply of 50 Hz or 60 Hz, and the touch-sensing part is likely to accidentally obtain noise generated from electrical appliances operated by such an external power supply. Therefore, as the frequency of the touch drive, a frequency different from the frequency of 50 Hz or 60 Hz, or a frequency slightly deviating from the integer multiple of these frequencies can be used, thereby greatly reducing the noise generated from the liquid crystal drive or external electronic equipment The impact of information. Alternatively, the application timing of the touch sensing driving signal and the application timing of the liquid crystal driving signal may be deviated on the time axis. The amount of deviation can be a number of amounts, for example, it can be a deviation of ±3% to ±17% of the noise frequency. In this case, interference with the noise frequency can be reduced. For example, the frequency of the touch drive, for example, can select a different frequency that does not interfere with the liquid crystal drive frequency or the power supply frequency from the range of 500 Hz to 500 KHz. A different frequency that does not interfere with the liquid crystal driving frequency or the power supply frequency is selected as the frequency of the touch driving, so that, for example, the influence of noise such as coupling noise under column inversion driving can be reduced.

In addition, in the touch sensing driving, the driving voltage is not supplied to all the touch sensing wirings 3, but as described above, the touch position detection is performed using the reduced driving, which can reduce the touch sensing Power consumption.

In the reduced driving, the wiring that is not used for touch sensing, that is, wiring with a floating pattern, can be switched to a detection electrode or a driving electrode by a switching element for high-definition touch sensing. Alternatively, the wiring with a floating pattern can also be switched to be electrically connected to the ground (grounded to the frame). In order to improve the S/N ratio of touch sensing, the signal wiring of active elements such as TFTs may be temporarily grounded to the ground wire (frame, etc.) during the detection of touch sensing signals.

In addition, the reset of the capacitance detected by the touch sensing control requires time for the touch sensing wiring, that is, the touch sensing wiring with a large time constant of touch sensing (product of capacitance and resistance value), for example It is possible to alternately use the odd-numbered rows of touch sensing wiring and the even-numbered rows of touch sensing wiring for sensing, and drive to adjust the magnitude of the time constant. A plurality of touch sensing wires can be grouped for driving or detection. The grouping of the plurality of touch-sensing wires may not be set as a line sequence, but adopts a one-time detection method called a self-detection method based on its group unit. Parallel driving based on group units can be performed. Alternatively, a differential detection method that obtains the difference in the detection signals of the touch sensing wires that are close to or adjacent to each other may be used for noise cancellation of parasitic capacitance or the like.

According to the above-mentioned first embodiment, it is possible to provide a liquid crystal display device with a high S/N ratio, a high resolution, and can respond to high-speed touch input LCD1. In addition, by adopting a thin film transistor using an oxide semiconductor as a channel layer, a liquid crystal display device with less flicker under low power consumption and having a touch sensing function can be realized.

(Modification of the first embodiment)

FIG. 19 is an enlarged cross-sectional view showing a main part of a liquid crystal display device according to a modification of the first embodiment of the present invention. In FIG. 19, the same components as those in the above-mentioned embodiment are given the same reference numerals, and their description is omitted or simplified.

In FIG. 19, the third insulating layer 13 formed on the array substrate 200, the protruding portion 13A formed on the third insulating layer 13, and the common wiring 30 formed on the protruding portion 13A are shown, and other insulating layers are omitted. , Wiring, electrodes, etc. The protrusion 13A is formed using, for example, an insulating material that forms the above-mentioned insulating layer.

In a plan view, the pattern of the protrusion 13A and the pattern of the common wiring 30 match. The height between the upper surface of the protrusion 13A and the upper surface of the third insulating layer 13 where the protrusion 13A is not formed is W3. As a method of forming the protruding portion 13A, after the third insulating layer 13 is formed in the above-described embodiment, the protruding portion 13A is additionally provided on the third insulating layer 13 previously formed on the fourth insulating layer 14 method. As a method for forming such a protrusion 13A, a well-known film forming step or patterning step can be used. The material of the third insulating layer 13 and the material of the protrusion 13A may be the same or different.

From the viewpoint of suppressing the noise caused by the image signal supplied to the source wiring 31 to the common wiring 30, the height W3 of the protrusion 13A can be appropriately set.

In particular, as shown in FIG. 5, the third insulating layer 13 functions as a gate insulating film between the gate electrode 25 and the channel layer 27, and a proper film thickness considering the switching characteristics of the active element 28 is required. Therefore, if it is also considered to suppress the noise caused by the image signal supplied to the source wiring to the common wiring 30 and realize the desired switching characteristics in the active device 28, the third insulating layer 14 must be The film thickness of the insulating layer 13 is partially different.

Therefore, first, on the fourth insulating layer 14, the third insulating layer 13 is formed with a proper thickness considering the switching characteristics of the active element 28, and then, on the third insulating layer 13, the noise-considered pair is formed in common. The protrusions 13A having a height W3 that are influenced by the wiring 30 further form a common wiring 30 on the protrusions 13A. With this structure, the thickness of the insulator between the common wiring 30 and the source wiring 31 (total of the film thickness of the third insulating layer 13 and the film thickness of the protrusion 13A) can be maintained at the channel layer. The thickness of the third insulating layer 13 directly above 27 is reduced. With this, it is possible to suppress the noise caused by the image signal supplied to the source wiring from being transmitted to the common wiring 30, and at the same time, the desired switching characteristics can be realized in the active element 28.

(Second embodiment)

The liquid crystal display device LCD2 of the second embodiment will be described using FIGS. 20 to 25. FIG. The same components as those in the above-mentioned first embodiment are given the same reference symbols, and their descriptions are omitted or simplified.

FIG. 20 is a plan view partially showing an array substrate 200 constituting the liquid crystal display device LCD2 of the second embodiment of the present invention, as viewed from the observer side.

Fig. 21 is a partial cross-sectional view of the array substrate 200 constituting the liquid crystal display device LCD2 of the second embodiment of the present invention, taken along line D-D' shown in Fig. 20.

FIG. 22 is a plan view partially showing a liquid crystal display device LCD2 according to a second embodiment of the present invention, shown on an array substrate 200, through a liquid crystal layer, a display device substrate laminated with a color filter and touch sensing wiring Structured plan view, plan view viewed from the observer side.

Fig. 23 is a partial cross-sectional view of the array substrate 200 constituting the liquid crystal display device LCD2 of the second embodiment of the present invention, taken along the line E-E' shown in Fig. 20.

FIG. 24 is a plan view partially showing a pixel of a liquid crystal display device LCD2 according to a second embodiment of the present invention, and showing a state of alignment of liquid crystal in one pixel.

FIG. 25 is a plan view partially showing a pixel of a liquid crystal display device LCD2 according to a second embodiment of the present invention, and a plan view showing a liquid crystal driving operation when a liquid crystal driving voltage is applied between a pixel electrode and a common electrode.

As shown in FIG. 20, the pixels included in the liquid crystal display device LCD2 of the second embodiment have a zigzag pattern (dog-legged pattern).

As shown in FIGS. 24 and 25, the common electrode 17 and the pixel electrode 20 have an inclined portion inclined at an angle θ with respect to the Y direction. Specifically, the common electrode 17 and the pixel electrode 20 in each pixel have an upper region Pa (first region) and a lower region Pb (second region). The upper area Pa and the lower area Pb are relative to the pixel center (the center line parallel to the X direction) Configured to be line symmetrical. In the upper region Pa, the common electrode 17 and the pixel electrode 20 are inclined at an angle θ clockwise with respect to the Y direction. In the lower region Pb, the common electrode 17 and the pixel electrode 20 are inclined at an angle θ counterclockwise with respect to the Y direction. By tilting the common electrode 17 and the pixel electrode 20 in this way, and applying rubbing treatment to the alignment film along the alignment processing direction Rub parallel to the Y direction, the liquid crystal molecules 39 can be given initial alignment in the Y direction. As the alignment treatment of the alignment film, light alignment treatment or brushing treatment can be used. There is no need to specify the angle θ, for example, the angle θ may be set in the range of 3° to 15°. In FIG. 20, the common electrode 17 is formed to have a stripe pattern, and has two electrode portions 17A formed in a zigzag shape. The contact hole H is located in the center of the conductive pattern (electrode portion 17A, zigzag pattern) of the common electrode 17.

As shown in FIG. 22, the source wiring 31, the black layer 8 (the Y-direction extending portion of the black matrix BM), the touch sensing wiring 3, and the red filter (R) and the green color that constitute the color filter 51 The filter (G) and the blue filter (blue) also have a zigzag pattern (broken line pattern).

In the example shown in FIG. 23, the channel layer 27, the source electrode 24, and the drain electrode 26 are formed on the fourth insulating layer 14. In the first embodiment described above, the source electrode 24 and the drain electrode 26 are formed on the channel layer 27 (FIG. 11 ), but in this embodiment, the channel is formed on the source electrode 24 and the drain electrode 26 Layer 27.

That is, in this embodiment, the source electrode 24 and the drain electrode 26 are formed on the fourth insulating layer 14 first. As the structure of the source electrode 24 and the drain electrode 26 in the second embodiment, a three-layer structure of molybdenum/aluminum alloy/molybdenum is used. Part of the channel layer 27 is electrically connected to the source electrode 24 and the drain electrode Pole 26 overlap. As a material of the channel layer 27, a composite oxide semiconductor of indium oxide, gallium oxide, and zinc oxide is used. Zinc oxide can be replaced by antimony oxide.

Next, the advantage that the pixel shape has the above shape will be described with reference to FIGS. 24 and 25.

FIG. 25 shows the liquid crystal driving operation when the liquid crystal driving voltage is applied between the common electrode 17 and the pixel electrode 20. The liquid crystal driving voltage is applied in the direction of the arrow from the pixel electrode 20 to the common electrode 17. As shown in FIG. 26, a fringe electric field is generated from the pixel electrode 20 toward the common electrode 17, and the liquid crystal molecules 39 are driven along the fringe electric field. Rotate in the direction of the arrow. The liquid crystal molecules 39 located in the upper region Pa of the pixel and the lower region Pb of the pixel rotate oppositely to each other as shown in FIG. 25. Specifically, the liquid crystal molecules 39 in the upper region Pa rotate counterclockwise, and the liquid crystal molecules 39 in the lower region Pb rotate clockwise. Therefore, optical compensation can be realized, and the viewing angle of the liquid crystal display device LCD2 can be increased.

In the present embodiment, as the liquid crystal molecules 39, liquid crystal molecules having positive dielectric anisotropy are used. In the case where liquid crystal molecules having negative dielectric anisotropy are used, it is difficult for the liquid crystal molecules to warp in the thickness direction of the liquid crystal layer 300. In this embodiment, the touch driving voltage is applied in the direction from the touch sensing wiring 3 toward the common electrode 17, that is, in the oblique direction inclined with respect to the thickness direction of the liquid crystal, so it is preferable to use a negative Liquid crystal molecules with dielectric anisotropy. As the liquid crystal material, for example, a high-purity material whose inherent low efficiency of the liquid crystal layer 300 is 1×10 ¹³ Ωcm or more is desirable.

According to this embodiment, in addition to the effects obtained by the first embodiment described above, the liquid crystal molecules 39 in the upper region Pa and the lower region Pb can be given initial alignment by performing the alignment processing direction Rub parallel to the Y direction. .

The advantages of this embodiment will be described more specifically with reference to FIG. 32.

FIG. 32 is an enlarged plan view of one pixel of the conventional liquid crystal display device using the FFS mode, and a plan view showing the array substrate. In FIG. 32, the pixel electrode 50 is located on the upper surface of the array substrate, and the common electrode 47 is located below the pixel electrode 50 through the insulating layer. The pixel electrode 50 and the common electrode system are formed of a transparent conductive film such as ITO. The pixel electrode 50 is electrically connected to the drain electrode of the thin film transistor 46 through the contact hole 48. The contact hole 48 is arranged near the thin film transistor 46 located at the upper end of the pixel electrode 50.

In such a conventional liquid crystal display device, it is necessary to extend the pixel electrode 50 from the position of the contact hole 48 so as to reach the maximum distance Pd. In this case, due to the relationship between the resistance value of the transparent conductive film forming the pixel electrode 50 and the position of the pixel electrode 50, the liquid crystal molecules at the position close to the contact hole and the position away from the contact hole (separated by the maximum distance Pd) There is a difference in responsiveness between liquid crystal molecules.

A major problem in the pixels constituting the conventional liquid crystal display device is that a dislocation region D of liquid crystal is generated in a position close to the contact hole of the pixel electrode formed with a plurality of stripe patterns (comb-tooth patterns). In the staggered region D, the direction of the power line 49 from the pixel electrode 50 toward the common electrode 47 changes, so that sufficient transmittance cannot be obtained, and the transmitted light may be discolored.

This embodiment is different from the conventional structure of the connection portion connecting the pixel electrode 50 and the thin film transistor 46 as shown in FIG. 32. In this embodiment, as shown in FIG. 20, any common electrode 17 is electrically connected to the conductive wiring (common wiring 30) through the contact hole H (LH, RH) located in the center in the longitudinal direction of the pixel Therefore, there is an advantage that the difference in resistance value of the transparent conductive film forming the common electrode 17 becomes smaller than in the conventional structure. Since the connection part of the pixel electrode of the above-mentioned conventional structure is not provided, the adverse effect of the liquid crystal misalignment region D hardly occurs.

In the above-mentioned embodiment, the stripe pattern or the dog-legged pattern extending in the Y direction has been described as the pattern of the common electrode 17, but the present invention is not limited to this structure. For example, a square pattern, a rectangular pattern, a parallelogram pattern, or the like can be used.

(Third Embodiment)

The liquid crystal display device LCD3 of the third embodiment will be described using FIGS. 27 to 29.

The same components as those in the above-mentioned first embodiment are given the same reference symbols, and their descriptions are omitted or simplified.

FIG. 27 is a plan view partially showing an array substrate of a liquid crystal display device according to a third embodiment of the present invention. FIG. 28 is a plan view partially showing a display device according to a third embodiment of the present invention, which is a plan view showing the structure of a display device substrate on an array substrate, through a liquid crystal layer, laminated with a color filter and touch sensing wiring , A plan view from the observer's side. FIG. 29 is a cross-sectional view partially showing an array substrate constituting a display device according to a third embodiment of the present invention.

The pixel opening 18 in the third embodiment is formed in a parallelogram shape with a different angle and a quadrangular shape in a plan view, and is arranged in the Y direction. Each pixel is divided into a matrix by the gate wiring 10 parallel to the X direction and the source wiring 31 of the pixels along the parallelogram. In FIG. 27, an active element 28 is provided on the upper right end of each of the pixel openings 18. The active element 28 includes a source electrode 24 connected to the source wiring 31, a channel layer 27, a drain electrode 26, and a gate electrode 25 disposed opposite to the channel layer 27 through an insulating film. The gate electrode 25 of the active element 28 constitutes a part of the gate wiring 10 and is connected to the gate wiring 10. In addition, the structure of the active element of the thin film transistor is the same as the structure shown in FIG. 5.

The pixel electrode 20 is electrically connected to the drain electrode 26 through the contact hole 29 located at the upper right corner of the pixel electrode 20 as shown in FIG. 27.

The common electrode 17 is formed to have a stripe pattern. Specifically, the common electrode 17 extends parallel to the extending direction of the pixel having a parallelogram shape in the Y direction (the direction inclined by the angle θ with respect to the Y direction), and is located in the center of the pixel opening 18.

One common electrode 17 is provided for each pixel. The angle θ is the inclination with respect to the Y direction in a plan view. In the lower part of each of the common electrodes 17, the pixel electrode 20 located under the first insulating layer 11 is provided on the cross section. In the center of the common electrode 17 in the Y direction, a third contact hole 43H is provided. The common electrode 17 is connected to the common wiring 30 (conductive wiring) through the third contact hole 43H.

In this embodiment, one common electrode 17 is provided for each pixel, and the number of third contact holes 43H is also one for each pixel. In order to distinguish it from the first contact hole LH and the second contact hole RH described in the first embodiment and the second embodiment, in the third embodiment, the contact hole that conducts the common electrode 17 and the common wiring 30 is called This is the third contact hole 43H. The angle θ is similar to the second embodiment, and can be set to an angle of 3° to 15°, for example.

The liquid crystal molecules are aligned parallel to the plane including the common electrode 17 or the pixel electrode 20, and the long axis direction is aligned parallel to the Y direction. This is liquid crystal driving in a so-called FFS mode driven by a liquid crystal driving voltage applied between the common electrode 17 and the pixel electrode 20.

The touch sensing is performed by detecting the change in capacitance between the touch sensing wiring 3 and the common electrode 17. The touch sensing wiring 3 and the common electrode 17 can use either one as a touch drive electrode and any one as a touch detection electrode.

FIG. 29 shows the distance W1 between the touch sensing wiring 3 and the common electrode 17. In other words, this distance W1 is the distance in the Z direction in the space including the transparent resin layer 16, the color filter 51 (RGB), an alignment film (not shown), and the liquid crystal layer 300. This space does not include active components, source wiring, and pixel electrodes. In the present embodiment, this space shown by the distance W1 is called a touch sensing space.

As shown in FIG. 27, the distance W4 between the common wiring 30 and the gate wiring 10 can be secured, so that the influence of the gate signal on touch sensing can be reduced. In addition, as shown in FIG. 29, the distance W2 between the source wiring 31 supplying the image signal and the touch sensing wiring 3 can be sufficiently ensured, so that the touch sensing given by the noise caused by the image signal can be reduced Impact.

The display device substrate of this embodiment includes a color filter 51 (RGB) including a black matrix, a black matrix BM, and a touch sensing wiring 3 provided on the black matrix BM on the liquid crystal layer side. In addition, when three types of LEDs of red LED, green LED, and blue LED are used in the backlight unit, the three colors are sequentially emitted by time-division driving, and the multi-color display in which the liquid crystal is synchronized can omit the color filter 51.

According to the present embodiment, it is possible to give different initial alignments to the liquid crystal molecules 39 of pixels adjacent to each other in the Y direction by performing an alignment processing direction parallel to the Y direction. In addition, the same effects as those in the first embodiment and the second embodiment described above can be obtained.

For example, the liquid crystal display device of the above-mentioned embodiment can have various applications. Examples of electronic devices to which the liquid crystal display device of the above-mentioned embodiment can be applied include mobile phones, portable game devices, portable information terminals, personal computers, e-books, video cameras, digital cameras, head-mounted displays, Navigation systems, audio playback devices (car audio, digital audio players, etc.), photocopiers, fax machines, printers, printer multifunction machines, vending machines, automatic teller machines (ATM), personal authentication machines, optical communication machines Wait. The above-mentioned embodiments can be freely used in combination.

The liquid crystal driving method applicable to the present invention is not limited to the liquid crystal driving method described in the above embodiment. For example, the liquid crystal driving method described below can be used.

For example, the polarity of the signal electrode (source wiring) in the active matrix may be inverted to drive the liquid crystal (for example, described in Japanese Patent No. 2982877).

In addition, in the active matrix driving of liquid crystal, the first signal line (source wiring) and the second signal line may be alternately replaced for dot inversion driving according to the horizontal period of liquid crystal driving (for example, described in Japanese Patent Laid-Open 11-102174).

In addition, in the active matrix driving of the liquid crystal, each pixel uses two source wirings as data drives (source wirings), and transmits image signals with different polarities to the data driving according to the amplitude for horizontal line driving (For example, it is described in Japanese Patent Laid-Open No. 9-134152).

In addition, in the active matrix driving of liquid crystal, each pixel may use two gate wirings as scanning signal lines (gate wirings). In this case, for example, data of opposite polarities are written to scan signal lines of odd rows and scan signal lines of even rows. In a certain display period, data of opposite polarities can be written to the odd and even columns of adjacent pixels, respectively, and in the next display period, data of opposite polarities can be written separately from the previous display period (for example, It is described in Japanese Unexamined Patent Publication No. 7-181927).

When the above-mentioned liquid crystal driving method is applied to the present invention, regardless of which method, the number of active elements (TFTs) per pixel may be a complex number of 1 or more. The above-mentioned liquid crystal driving technology can be applied to the present invention.

The preferred embodiments of the present invention have been described above, but the above description is an illustration of the present invention, and it should be understood that they should not be used to limit the present invention. Additions, omissions, substitutions, and other changes can be made without departing from the scope of the present invention. Therefore, the present invention should not be regarded as limited by the foregoing description, but by the scope of patent application.

3‧‧‧Touch sensing wiring

8‧‧‧Black layer

11‧‧‧The first insulating layer

12‧‧‧The second insulating layer

13‧‧‧The third insulating layer

14‧‧‧The fourth insulating layer

16‧‧‧Transparent resin layer

17‧‧‧Common electrode

17A‧‧‧Electrode

18‧‧‧Pixel opening

20‧‧‧Pixel electrode

21‧‧‧Transparent substrate (1st transparent substrate)

22‧‧‧Transparent substrate (second transparent substrate)

30‧‧‧Common wiring (conductive wiring)

31‧‧‧Source wiring

51‧‧‧Color filter

100‧‧‧Display device substrate

200‧‧‧Array substrate

300‧‧‧Liquid crystal layer

L‧‧‧Light

LCD1‧‧‧Liquid crystal display device

W1‧‧‧Distance between touch sensing wiring and common electrode

W2‧‧‧Distance between touch sensing wiring and source wiring

BU‧‧‧Backlight unit

Claims (13)

A display device includes a display device substrate, an array substrate, a display function layer, and a control unit. The display device substrate includes a first transparent substrate and a touch extending in the first direction provided on the first transparent substrate Sensing wiring, the array substrate includes: a second transparent substrate; a plurality of polygonal pixel openings on the second transparent substrate; a common electrode having a plurality of pixel openings provided in each of the plurality of pixel openings and viewed in plan One or more electrode portions extending in the first direction; a first insulating layer provided under the common electrode; a pixel electrode provided in the first insulating layer in each of the plurality of pixel openings The second insulating layer is provided under the pixel electrode; the conductive wiring is electrically connected to the common electrode under the second insulating layer, and extends in the second direction orthogonal to the first direction and spans The plurality of pixel openings; a third insulating layer, disposed under the conductive wiring; an active element, a thin-film transistor of a top gate structure disposed under the third insulating layer and electrically connected to the pixel electrode; The wiring has the same layer structure as the conductive wiring, is formed at the same position as the conductive wiring between the second insulating layer and the third insulating layer, and extends in the second direction in plan view to be The active element is electrically connected; the source wiring extends in the first direction in a plan view to be electrically connected to the active element; and the contact hole is provided at the center of the longitudinal direction of the pattern of the electrode portion and is electrically Connect the common electrode and the conductive wiring, The display function layer is sandwiched between the display device substrate and the array substrate, and the control unit drives the display function layer by applying a driving voltage between the pixel electrode and the common electrode to perform image display. Detecting a change in capacitance between the common electrode and the touch sensing wiring for touch sensing, in a diagonal direction inclined with respect to the thickness direction of the display function layer, the touch sensing The test wiring and the common electrode system are opposed to each other. The display device of claim 1, wherein the common electrode has a stripe pattern extending in a long direction parallel to the touch sensing wiring in a plan view. The display device according to claim 1, wherein the active element is a thin film transistor, and the thin film transistor system includes a channel layer made of an oxide semiconductor, and the channel layer is in contact with the gate insulating film. The display device according to claim 3, wherein the oxide semiconductor is an oxide semiconductor including two or more kinds of metal oxides among gallium, indium, zinc, tin, aluminum, germanium, antimony, bismuth, and cerium. The display device according to claim 3, wherein the gate insulating film is a gate insulating film formed of a composite oxide containing cerium oxide. The display device according to claim 1, wherein the display function layer is a liquid crystal layer, and the liquid crystal of the liquid crystal layer has an initial alignment parallel to the array substrate, by applying a liquid crystal driving voltage applied between the common electrode and the pixel electrode The generated fringe electric field is driven. The display device according to claim 1, wherein the common electrode and the pixel electrode are composed of a composite oxide containing at least indium oxide and tin oxide. The display device according to claim 1, wherein the touch sensing wiring is composed of a metal layer including a copper alloy layer. The display device according to claim 1, wherein the touch sensing wiring has a structure in which a copper alloy layer is held by a conductive metal oxide layer. The display device according to claim 1, wherein the conductive wiring has a structure in which the copper alloy layer is held by the conductive metal oxide layer. The display device according to claim 9 or 10, wherein the conductive metal oxide layer includes a composite oxide layer of two or more of indium oxide, zinc oxide, antimony oxide, and tin oxide. The display device according to claim 1, wherein the display device substrate includes a black matrix disposed between the first transparent substrate and the touch sensing wiring, and the touch sensing wiring overlaps a part of the black matrix. The display device according to claim 1, wherein the display device substrate includes a color filter provided at a position corresponding to a plurality of pixel openings.

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